Regular Expressions - Examples and Use Cases

Background

This post should serve as a repository of selected use-case reqular expressions, sorted by utility/name. It is predominantly centered around Linux and user-space utilies (with a certain amount of Cisco IOS-based examples as well in its heading and subheadings). It will hopefully be continually updated as I intent to keep adding to it as I see buld more regular expression use cases.

MDADM

The following was useful to gather mdadm information when I had an issue with a missing block device in a RAID array (which turned out to be SATA cables that where accidently swapped when performing maintenance/cleaning causing device unexpected device renaming which ultimately bumped a device off the array - sdb in my case). The examples here uses simple patterns to show the linux block devices in an array and looking for log entries

user@host:~$ sudo mdadm --detail /dev/md0 | egrep '\/dev\/sd?'
       3       8       64        0      active sync   /dev/sde
       1       8       32        1      active sync   /dev/sdc
       4       8       48        2      active sync   /dev/sdd
user@host:~$ cat /etc/mdadm/mdadm.conf | egrep '\/dev\/sd?'
DEVICE /dev/sdb /dev/sdc /dev/sdd /dev/sde
user@host:~$
user@host:~$ sudo dmesg | grep md0
[    2.701684] md/raid:md0: device sdc operational as raid disk 1
[    2.701686] md/raid:md0: device sdd operational as raid disk 2
[    2.701687] md/raid:md0: device sde operational as raid disk 0
[    2.702549] md/raid:md0: raid level 5 active with 3 out of 3 devices, algorithm 2
[    2.702574] md0: detected capacity change from 0 to 8001304920064
user@host:~$ 

HDPARM

For similar reasons to the MDADM, I initially suspected that a disk was faulty and wanted to extract the serial numbers of each for warranty lookup. This is how I acheived that outcome (sans actual serial numbers).

user@host:~$ sudo hdparm -I /dev/sd? | egrep '(\/dev\/sd?|Serial\ Number)'
/dev/sda:
        Serial Number:      *** REDACTED ***
/dev/sdb:
        Serial Number:      *** REDACTED ***
/dev/sdc:
        Serial Number:      *** REDACTED ***
/dev/sdd:
        Serial Number:      *** REDACTED ***
/dev/sde:
        Serial Number:      *** REDACTED ***
user@host:~$

SCREEN

So, sometimes a screen is killed or exited (often accidently) and rather than opening up the local user screenrc file, looking for the screen/entry/command and then executing the screen command manually to restore it, with the help of grep, I simply execute it dirrectly with bash substitution. Here are a couple of examples:

$(grep virsh ~/.screenrc)
$(grep /var/log/messages ~/.screenrc)
$(grep virt_snapshot ~/.screenrc)

LVM

At some point, we might need to review LVM volumes to see where we can scale and resize etc. The following allowed me to quickly see everything at a glance in order to formulate a plan for resizing.

user@host:~$ sudo lvdisplay | egrep "LV (Name|Size)"

[sudo] password for user:
  LV Name                video
  LV Size                <4.02 TiB
  LV Name                audio
  LV Size                750.00 GiB
  LV Name                hdimg
  LV Size                <2.51 TiB
  LV Name                swap
  LV Size                16.00 GiB
  LV Name                var-tmp
  LV Size                8.00 GiB
user@host:~$

Cisco IOS

A collection of various Cisco IOS commands and the very limited IOS regular expression engine on an IOS device (or IOS-XE's IOSD).

show version

Show a consolidated view of uptime, firmware and software version & reason for reload (minus all the Cisco copyright and releng information):

SWITCH#show ver | incl Cisco IOS Software|(ROM|BOOTLDR)|uptime|System (returned|restarted|image)

Cisco IOS Software, C3750 Software (C3750-IPSERVICESK9-M), Version 15.0(2)SE11, RELEASE SOFTWARE (fc3)

ROM: Bootstrap program is C3750 boot loader

BOOTLDR: C3750 Boot Loader (C3750-HBOOT-M) Version 12.2(44)SE5, RELEASE SOFTWARE (fc1)

SWITCH uptime is 1 week, 3 days, 22 hours, 29 minutes

System returned to ROM by power-on

System restarted at 12:28:16 WST Sun Sep 17 2023

System image file is "flash:/c3750-ipservicesk9-mz.150-2.SE11.bin"

SWITCH#

show etherchannel

Show portchannel member state times - This is particularly useful in correlating events for possible cause without having to rely on syslog:

SWITCH#show etherchannel 1 detail | incl ^(Port: |Age of the port)

Port: Gi1/0/15

Age of the port in the current state: 10d:22h:41m:32s

Port: Gi1/0/16

Age of the port in the current state: 10d:22h:41m:31s

Port: Gi1/0/17

Age of the port in the current state: 10d:22h:41m:30s

Port: Gi1/0/18

Age of the port in the current state: 10d:22h:41m:30s

SWITCH#

Cisco IOS IPv6 observations

I wanted to delve deeper into some of the intricacies of IPv6, specifically Neighbour discovery and Directly attached Static routes as well as OSPFv3 using the legacy configuration. I recently discovered two odd Cisco behaviours with these following topics, possibly related to virtual lab devices, so not tested on real equipment.

1. IPv6 Directly Attached Static Routes
2. OSPF IPv6

IPv6 Directly Attached Static Route

This doesn't seem to work as described (at least not in a lab). Only fully-specified or a net-hop static route works. This could be due to either;

• No MAC address to IPv6 neighbor binding - since IPv6 doesn't use the concept of ARP like IPv4 does, it instead relies on Neighbor discovery, which doesn't seem to work - more testing/research is required.
• Limitation with the way Layer 2 forwarding is handled in an Emulated/Virtual environment.

OSPF IPv6

The protocol, according to some old Cisco Press article I dug up[1]. It appears to "leverage" the OSPFv3 engine, however it can be configured/started using the legacy IPv6 OPSF configuration similar to IPv4 as per the following:

ipv6 ospf process-id

Now, if there's an existing, legacy OSPF IPv4 configuration using the same process-id, it appears to silently fail when entering the configuration (except perhaps if you enable debugging). No neighbours will establish at all, despite documetation claiming that it migrates it to the OSPFv3 configuration (it most likely does this internally though as I observed that the configuration stays pretty much as you entered it in both running and start-up configuration).

The lesson I learned here, is to identify if multiple OSPF address-families share the same process in legacy configuration mode and either;

1. Update all your configuration so that one of the "confliting" addresss families is unique or
2. You migrate the conflicting processes/address families to the new OSPFv3 configuration as a consolidation of address families under the one process.

Further to the above, when removing an OSPF process with no ipv6 ospf process-id, any interface-specific IPv6 process/area configuration is also removewd without warning.

[1] https://www.ciscopress.com/articles/article.asp?p=2294214&seqNum=4

HomeLab Mk.3 - Planning Phase

Background

I kicked off my homelab refresh project not long ago, dubbed "HomeLab mk.3" as its the third iteration since circa 2010. I'm now well into the planning phase but I've found that I'm also overlapping into the procurement phase (as described herein).

So far, I've decided to replace my pre-Ryzen AMD-based full-tower hyperconverged system with another hyperconverged system, but this time it will be housed in an 18RU rack for providing a small amount of noise management, but also neaten up the office a little, which will have the added benefit of assisting in home improvement (flooring) later.

Key requirements;

1. Costs must be kept as low as possible
2. Software RAID (due to #1)
3. Hyperconverged system (due to item #1 and power constraints)
4. Nested virtulisation for EVE-NG/network modelling

Therefore based on requirements, the system (excluding the rack) will comprise of the following;

• One SSD for the hypervisor stack/host OS
• Up to six (6) 8Tb CMR disks for the storage of guests etc.
• 4RU ATX rackmount case (including rails of course) ✅
• As much memory as the mainboard allows which relates to key requirement #4

Challenges

The current challenges surrounding the build are;

1. Choice of Hypervisor (oVirt, libvirt, OpenStack, EVE-NG)
2. Choice of CPU architecture (due to key requirement #4 and likely challenge #1)
3. Possible Network re-architecture required to support the system including possible infrastructure Re-IP addressing.

Choice of Hypervisor

For item #1 the choices don't look that great, and I will probably stick with libvirt and the various virt toolsets, only because;

• oVirt appears to no longer be supported downstream by RedHat which means contributions to the upstream project (oVirt) will likely and eventually kill the project
• OpenStack is a pain to set up, even the all-in-one "packstack" which also means that could impact scalability in future if required
• EVE-NG appears to be an inappropriate choice. While it supports KVM/QEMU/qcow2 images, I'm not sure I want this as the underlying HomeLab hypervisor (unless certain constraints can be overcome - these are considered not in scope of this post).

Choice of CPU architecture

For item #2 the CPU architecture is important only because network vendor (QEMU/qcow2) images highlight strict CPU architecture requirements as being Intel-based, and AFAIK nested virtulisation requires that the guest architecture matches that of the host.

Possible Network re-architecture

Item #3 is not insurmountable, but it is still a challenge nonetheless as I'm not sure about whether I will change the Hypervisor guest networks (dev, prod, lab etc) to connect back upstream at L2 or L3.

Procurement

As I mentioned already, the project planning phase is somewhat overlapping with the procurement phase, the reason for this is so that I can not only procure certain less tech-depreciating items over time to allow project budget flexibility, but also allow a certain level of reduced risk in operation of the system:

Case in point: HDD's - I never risk buying them from the same batch in case of multiple catastrophic failures.

I've already purchased 3 HDD's, the 4RU rackmount case and rails and an 18RU rack to house the new gear along with the existing kit (switch, router and UPS).

I'll continue to procure the HDD's until I have enough to build the system then all that left is to purchase the key parts for the rack mount case/system (CPU, mainboard, memory & PSU) once CPU architecture/hypervisor testing (see Hardware selection below) and the design is complete.

Hardware selection (CPU architecture)

In order to determine whether the new system will be Intel or AMD will depend on the testing performed on my AMD Ryzen-based desktop. If EVE-NG and the required images work in nested virtualisation (and/or bare-metal) with said CPU architecture, then I will be in a good position to stick with AMD for this iteration (and likely future iterations) of the HomeLab. After all, AMD-based systems appear to have a good pricepoint which relates back to key requirement #1

EVE-NG and IOL copy run unix:

Lately, I've found myslelf working more on EVE-NG than the Cisco Learning Labs (CLL) which has allowed me to go beyond the constraints of the traditional learnings and key topics and allows me to tinker more than I probably should.

A long time ago I thought that EVE (possibly pre-NG) allowed the user to litterally download the text file of the running config to file instead of having to rely on term len 0, show run and screen-scraping the contents and then offloading the resulting clipboard to a file and saving it *yawn*

Today I discovered that you can save a config straight to a file in EVE-NG on the linux filesystem (at least you can with IOL).

The way to do this is simply use the copy command with unix:file as the destination, replacing file with the name of the file;

R1#copy start unix:r1.txt 

Destination filename [r1.txt]? 

1683 bytes copied in 0.011 secs (153000 bytes/sec)

R1#

It is litterally that simple.

You can then find the file under the EVE-NG staging area, which you can then work on as a plain-text file;

root@eve-ng:~# ls -alh /opt/unetlab/tmp/1/e6eadfea-e000-41d7-abe9-98f8004bb23f/1 | egrep "r.\.txt$"

-rw-rw-r-- 1 unl1 unl 1.7K Sep 19 16:40 r1.txt

root@eve-ng:~#

I can only imagine how useful this could be in reverse by merging config snips straight from the emulated nodes off the host filesystem and perhaps even generating templates for labs etc.

More testing is required.

X11 Forwarding woes

Here is a very quick post. It's for a very common/annoying Linux X11/Forwarding quirk which I previously forgot what the solution was and decided that I would add it into my blog as a reference

Background:

When working on my Development laptop remotely with a LiveUSB (for either ripping audio or video content or using it as a dev environmenmt for my recent study), I found that having to setup/install packages locally with tge laptop keyboard/trackpad was anoying when having to constantly switch (physically) from main desktop to the laptop. Thanks to SSH most setup and interactions with the machine can be done from another machine.

The Problem:

Having SSH access is nice, but having access the locally installed browser and other apps displayed locally (via X11Forwarding) is even better (purely so I can avoid having to transfer downloaded content).

Some applications wil just work without changing anything, others (read: Firefox) require a little more persuaion to work.

This is kind of what it looks like out of the box on the host (with X11 Forwarding enabled in sshd and configured on the client SSH application):

kubuntu@kubuntu:~$ firefox &

[2] 17790 

kubuntu@kubuntu:~$ PuTTY X11 proxy: Unsupported authorisation protocol

Unable to init server: Broadway display type not supported: localhost:10.0

Error: cannot open display: localhost:10.0

[2]+  Exit 1                  firefox

kubuntu@kubuntu:~$

The solution:

For me it was quite simple (not sure if this will work for others though so YMMV).

Update the $DISPLAY environment variable:

export DISPLAY={{ x11_server }}:0.0

Where {{ x11_server }} is the hostname or IP address of the X11 Server (XLauch or whatever).

There, now I shouldn't forget this ever again :-D

Additional information:

1. This solution also seems to work inside individual screen sessions.
2. Source of the solutiuon (#2 in the list) was rediscovered at https://stackoverflow.com/questions/61221498/x11-forwarding-works-on-ubuntu-using-windows-10-cmd-line-ssh-only-after-first-us

Adventures in Open Source (Part 3)

The (somewhat) popular Adventures in Open Source series is back and even better than before

SYSLINUX
Along time ago and, I was able to force a Toshiba Satellite A10 to boot a Ghost Boot Wizard created disc (ISO) thanks to syslinux.
This seemed kind of tricky to begin with but looking back on it, it is pretty trivial.

First of all I mounted the ghost iso file as loopback and copied the file contents to a temporary directory ($pathspec can be any empty temporary directory such as /tmp/ghost).

sudo mount -o loop /usr/temp/ghost.iso /mnt/loop0
cp -R /mnt/loop0/* $pathspec

Next up I copied the necessary syslinux files to the temporary directory

cp /usr/lib/syslinux/isolinux.bin $pathspec
cp /usr/lib/syslinux/memdisk /$pathspec

I then had to create an isolinux configuration file called isolinux.cfg in the temporary ($pathspec) directory with the following contents.

cat > $pathspec/isolinux.cfg
default ghost
timeout 150
prompt 1
label ghost
  kernel memdisk
  append initrd=osboot.img
^Z

Lastly, I moved up one directory and created the iso with mkisofs/genisoimage

cd ..
mkisofs -v -J -V $volid -N -A '' -sysid '' -o $filename -b isolinux.bin -c boot.cat \
-no-emul-boot --boot-load-size 4 -boot-info-table $pathspec

That's all!

NOTE: Due to the varying nature of Linux distributions, I have purposefully used variables (named in accordance with mkisofs/genisoimage documentation) so as to aid in making this procedure as dynamic as possible.


ntfsclone(8)
Since I still help people with Windows (only close friends and relatives now), and I decided to give this tool another try (last time I used it, I used the "special" image format, which cannot be loopback mounted).

Bellow is the output (proof) of a successful ntfsclone (and ntfs-3g loopback mount).

localhost ~ # ntfsclone -o /u1/S3A1378D001-ntfsclone.img /dev/sde1ntfsclone v2.0.0 (libntfs 10:0:0)NTFS volume version: 3.1Cluster size       : 4096 bytesCurrent volume size: 39999500288 bytes (40000 MB)Current device size: 39999504384 bytes (40000 MB)Scanning volume ...100.00 percent completedAccounting clusters ...Space in use       : 13676 MB (34.2%)Cloning NTFS ...100.00 percent completedSyncing ...

This is me loopback mounting a standard ntfsclone (not special image format) image:

ntfs-3g -o loop /u1/S3A1378D001a-ntfsclone2.img /mnt/loop0mount | grep fuse/u1/S3A1378D001a-ntfsclone2.img on /mnt/loop0 type fuse (rw,noatime,allow_other)

[Cisco] Static Route Leaking

So, I had specific use case for allowing access to loopbacks on the same VRF across a point to point link without the need for a routing protocol.

None of the resources I found online gave a specific example of how to do this, however after some trial and error and piecing together various parts of specific solutions for use cases with much more elaborate designs, I came up with the following solution.

R2#show run int lo 1

Building configuration...

Current configuration : 156 bytes

!

interface Loopback1

description Management

vrf forwarding MGMT

ip address 192.168.10.2 255.255.255.255

end

R2#show run | incl ip route

ip route 192.168.10.2 255.255.255.255 Loopback1 name R2_LO1

ip route vrf MGMT 192.168.10.1 255.255.255.255 192.168.1.1 global name R1_LO1

R2#ping vrf MGMT 192.168.10.1

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 192.168.10.1, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/1 ms

R2#ping vrf MGMT 192.168.10.1

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 192.168.10.1, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/1 ms

R2#ssh -vrf MGMT -l admin 192.168.10.1

Password:

R1#show run int lo 1

Building configuration...

Current configuration : 144 bytes

!

interface Loopback1

description Management

vrf forwarding MGMT

ip address 192.168.10.1 255.255.255.255

end

R1#show run | incl ip route

ip route 192.168.10.1 255.255.255.255 Loopback1 name R1_LO1

ip route vrf MGMT 192.168.10.2 255.255.255.255 192.168.1.2 global name R2_LO1

R1#ping vrf MGMT 192.168.10.2

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 192.168.10.2, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/1 ms

R1#

So based on the above, you not only have to inform the global routing table (underlay) how to get to it's own loopback, but you also have to inform the VRF to use the GRT to transport traffic for the destination IP, in this case the host route.

Adventures in docker and portainer

Around 2007 I was gifted some old hardware which entailed an ASUS motherboard, 8Gb or RAM and an AMD CPU.

It wasn't until a few years later that I decided to build it into a home server.

There was no hardware virtualisation and either I didn't know how to do or didn't want to do software virtualisation and software RAID, instead all my services, DHCP, DNS, SAMBA, FTP etc. and I think even Plex as well (or maybe that came later) was running co-resident on a bare-metal JBOD server.

Since it was simple design, it was relatively simple to operate and maintain. I even managed to successfully P2V the server when I did a hardware refresh and it continued operating for the most part.

One day I upgraded the system and a Python-based application which catastrophically broke and I since abandoned picking it back up until recently because I discovered Docker containers.

Fast-forward to today, now I have a big proponent of my services and apps hosted in a dedicated docker-engine VM and maintenance has never been easier.

I've even learned how to share the same network namespace as other containers such as stacking a container with a VPN container and all it took was using the following in the compose file under the containers service definition:

network_mode: "container:<container>"

Which, I leaned and adapted the above from the following YouTube video:

How to route any docker container through a VPN container

Further to this my Docker engine VM is exclusively managed now using portainer.io where I can easily create and delete (and in the process upgrade) containers with ease, which means everything stays fresh and all I have to be concerned about is backing up the persistent storage!

Armed with knowledge of how docker works, I've written up slide deck on docker to help demystify docker containers and hopefully improve overall understanding for the potentially emerging DevOps capability.

Adventures in Automation: Part 1

So ever since I heard about automation (and then orchestration) I have finally taken some measures to not only learn but implement some of my own.

Since I realised that I have a reasonable amount of unwanted technical debt building up while having to maintain my 'homelab' in its current state, some the daily hastles can be automated away.

Two such tasks I have just undertaken and completed are"

1. Ansible automation to update, upgrade and clean orphaned/unused packages
2. Script to cleanup snapshots taken prior to ansible playbooks being run

I have a very long way to go before I can get other things automated, but its a start.

I'm also in the process if defining a docker environment where most of my services will operate from within one or more virtual machines.

I will also have to look into github repository of my code and a complete cloud backup solution with onsite encryption (encryped using my own privately owned and stored keys).

Free Range Routing

Since I discovered Docker, I have been busy designing my homelab to be as Cloud Native as possible, but in doing so, I realised that the default docker network (aka bridge) and the other networks defined by other containers from docker-compose bridge type networks isn't known by the upstream network collapsed core access layer network.

In the past I have been adding static routes upstream and a default route on the docker host, but this was not ideal (read scalable) given the dynamic nature of docker networks created with docker-compose.

I quickly realised that since I've developed significant experience in BGP (in service provider environments), I planned to just peer the docker host to the upstream access layer, but until now didn't know how to do this with Linux.

I have always known about Quagga, but been a bit concerned about the learning curve required to get it working, but remembered about its fork called Free Range Routing. So I decided to make the a leap of faith and I have no regrets whatsoever.

I was supprised at how easy it was to install and configure and to get it working which comprised of the following;

On the Docker host;

1. Setup the REPO
2. Installed FRR and configred services for vtysh as per the official documentation
3. Connected to the vtysh interface and
4. Configured BGP and redistributed only conneted routes using route-map/prefix-list

On the upstream switch/access layer;

1. Configured peering to FRR and squelched all but a summary route prefix-list/route-map.

Not only did I define the policies perfectly (woot!), but the neighbor came up without any issues at all!!!

My switch can now route traffic to any docker/docker-compose containers/services that are created with far less effort required to define routes to the containers as well as deleting them if no longer in use.

I am very supprised to learn that not only is it extremely easy to get FRR up and running but it is very easy to configure routing daemons/config for them especially if you have a grounding in Cisco as its vtysh is very closely matched with that of Cisco CLI - there are some slight and obvious differences to Cisco's not to mention the fact that you need to connect to the vtysh interface kind of like the root user does on a Juniper platform (cli).

Next up I need to figure out how to leverage Linux VRF namespaces using FRR vtysh, then I can migrate my infrastructure to MPLS!

juniper-nuances-part1

Once day I was relaiming an interface on my newly aquired Juniper SRX300 (yes, I managed to get one of these nice little units!) and when trying to commit, I came accross the below error, which wile it seems a little misleading, it actually gives a very good clue at the issue (which may seem cryptic to the inexperienced user).

root@srx300# set interfaces ge-0/0/1 unit 0 family ethernet-switching interface-mode trunk
[edit]
root@srx300# set interfaces ge-0/0/1 unit 0 family ethernet-switching vlan members all
[edit]
root@srx300# commit check
[edit routing-instances emetric interface]
  'ge-0/0/1.0'
    Interface with 'interface-mode' is allowed only in a virtual-switch
error: configuration check-out failed: (statements constraint check failed)

In the above example, the system claims that 'the interface-mode is allowed only in a virtual-switch' however upon removing the associated interface from the routing-instance (in this case I just deleted the routing instance) and making sure that the following was in place, then commit was successful and no further errors.

[edit]
root@srx300# delete routing-instances emetric
[edit]
root@srx300# commit check
configuration check succeeds
[edit]
root@srx300# show interfaces ge-0/0/1 | display set
set interfaces ge-0/0/1 unit 0 family ethernet-switching interface-mode trunk
set interfaces ge-0/0/1 unit 0 family ethernet-switching vlan members all

So, you see the lesson here is READ the output carfeully for the clue as to why the commit is throwing an error. In my case the interface was assigned in a routing-instance and therefore mutually exclusive when the interface is a L2 trunk (highlighted text).

NBN: The Somewhat Expected Journey

In the beginning

About three and a half years ago I was planning on purchasing a house with my then-girlfriend and choose a location that was earmarked to get Fibre to the Premise (FttP) National Broadband Network (NBN)​ with a three year build date. Within a few months of settlement an election was called and my location was wiped off the NBN map completely.

Three years on and I receive an email from my ISP advising that HFC is going to be available. Then junkmail in the mailbox with offers from one random unknown and a couple of known much disliked Retail Service Providers (RSP) - in the NBN world, they are now referred to as Retail Service Providers (RSP) and formally known as Internet Service Provider (ISP). Yes there is a difference.

The only thing that I think our government may have managed to achieve with their three words slogan for NBN during their campaigning is simply "cheaper" They appear to failed on the "faster" and "sooner" parts.

Back on track with the story, I jumped at the RSP email and decided to 'pre-order' my NBN (which turned out to be a mistake) as I learned from an NBN representative that that a pre-order is actually a new order and would have created a whole new account not linked or related to my existing, long tenure one, which I want to keep at least until the day I decide to switch to a new RSP. But that's not all I learned, just not from my RSP.

Curse of the cabling

Not only did I not realise that there was an existing Telstra cable/Foxtel box out the front of the house from a previous owner/residents installation, but it was in an inconvenient location and I needed to remediate the coax cabling before the NBN appointment (to install the Network Termination Device (NTD) - otherwise known as an NBN "Connection Box".

So in preparation for the NBN appointment, I decide to cancel the NBN order (also under advise by the RSP), except I wasn't quick enough to cancel the router that was immediately sent out. No biggie. It only cost $10 to have it sent to me.

So that brings me to the next part. The cabling. I forgot about the existing Telstra cable box at the front of the house outside, but since there was also foxtel dish on the roof (I actually thought the foxtel dish was the source of the cabling point), so I decided to remove the foxtel dish, but not before a trip to Bunnings to get two blank wall plates so that I could make it appear as though nothing was cabled or points inside the house, whereby upon removing said dish, I discovered that the dishes cable didn't actually go to the wall point I expected, but I continued to remove it anyway, putting aside the dish, mounting bracket and cable once removed.

I then located the actual coax cable drop (after realising/remembering about the cable box out front. Derp) and proceeded to pull that across to the (new) location where I wanted it. At this point I realised I had to go to Bunnings again, this time for an electrical snake, electrical tape, 16mm masonry drill bit and a new coax f-type wall plate.

Thinking that I had everything I needed, I tidied up the wall plates from the previous coax cable points and started to painstaking pull the existing cable through the roof eves trying to keep minimal turns to maximise length only to find out that the cable still fell short of approximately three metres. Being the engineer that I am, I saved myself I some money by reusing the cable from the foxtel dish I removed earlier and joined the coax with a connector salvaged from a removed f-type wall plate. Brilliant!

So after wrapping the join with a generous amount of electrical tape, there was more than enough length for the cable to reach the new wall point, for which was not as straight forward as just drilling a forty five degree hole to the wall cavity as I managed to loose the coax connector after I managed to get the snake and cable wedged in the bend of the newly drilled hole thinking I could stupidly un-wedge it by pulling harder on the snake then on the actual cable (minus the connector) and then on the snake again - finally dislodging the snake (minus the connector - which now lives somewhere inside the cavity walls). All this only because I mistakenly taped the coax cable and it's connector to the top of the snake instead of the bottom to allow it to go around the the bend of the newly drilled hole for the wall plate. Lesson learned.

Once I had the coax pulled through, I went off to Jaycar this time to get the replacement F-type connector (including a spare in case I borked it), but quickly realised that they were for a coax cable with a smaller core, so after yet another trip to Bunnings for the correct F-type connector, I got the wall plates finished and titles put back on the roof. Lucky for me I didn't break any tiles during the walking about on the roof!

Order in the court!

After all the saga of cabling was completed, I contacted my RSP and requested a new NBN order, this time under my existing account. So far so good except I receive another email telling me a router is being delivered. Again.

The next day I contact my RSP via reply email for the hardware order asking to cancel it. No response. I call them the following day to cancel it. They tell me there is no evidence of any charge but by that time I already have an email telling me it's been dispatched and on its way (It arrived the next day shoved into the mailbox, whereas the previous one I had to sign for at the local post office).

At this point the NBN appointment to install the NTD had also been brought forward but in the meantime I decided to break open the HG659b since I had two of them, so one of them was doomed to become my sacrificial test unit (read on to find out how/why).

./hack

Hacking the sacrificial unit involved soldering header pins to the empty holes where a serial port has been identified thanks to an openwrt hardware wiki article on it. De-soldering the factory solder points to put the header pins took far longer than actually soldering on the header pins though.

Having access to the serial port it was easy to get into the Common Firmware Environment (CFE) by interrupting the boot sequence so that I could flash spark (NZ) firmware onto this unit as it was more likely to include the download configuration file exploit not available in the crippled TPG firmware.

After doing the configuration file download exploit on the sacrificial unit with alternative firmware, I decrypted the configuration file with the help of a whirlpool knowledge article, and then the root password from the modified unit, I was then able to successfully use those credentials to log into the unmodified unit with normal, unadulterated, uncripled access.

With noob access defeated, I quickly discovered that not only does the unit only allow static routes, on the WAN interfaces but it is very picky about its LAN management IP address and subnet mask. According to the admin UI, apparently 192.168.2.1/24 is invalid and the Command Line Interface (CLI) over telnet is cripled and you cannot get a shell whatsoever. By this stage you can probably imagine the eyetwitch starting.

By now, it was blindingly clear that the HG659b is complete rubbish (ESPECIALLY WITH TPGs CRIPLED FIRMWARE!) - even more so for a network engineer such as myself.

In between all this, the NBN contractors had attended the premises (at the very end of the appointment window no less) to install the NTD (yes, it took two of them) and found the existing Telstra cable to have no signal! Thinking that it was my fault, I simply explained that I "had the the wall point moved". They then opened up the telstra cable box out front and not only found two cables coming from it but one of them was not connected - which was obviously the one I had remediated. They switched the cabling and the line had signal and they where able to activate it. By now one of the NBN contractors - what looked like the junior of the two - had left. The NBN contractor then used the excuse that his phone battery was flat so that he didn't have to wait around for the half an hour for confirmation of the service being activated. I wonder where the other cable leads to then?

MOAR HARDWARE!

Knowing that the HG659 is completely useless to me for my requirements, I dug around for an OpenWRT compatible router (not an AP and ADSL and everything all-in-one-gateway-that-everyone-calls-a-damn-router!) and settled on a MikroTik RouterBoard RB750GL from WISP - these guys have a questionable website security wise (certificate is fine but pages may include a form(s) with a non-secure "action" attribute.) but they shipped this thing in record time!

With the new router in hand I took a quick look at the very ugly UI for RouterOS and promptly installed OpenWRT on it using a combination OpenWRT installation methods from both the device page and the general common procedures (the latter of which mentions the missing initrd).

Before I got it off the default IP address (and adding a static summary route for all my subnets), I realised was getting annoyed at this point having to deal with equipment which ships with IP addresses which conflict with my own network, so I decided to change my Local Area Network (LAN) subnet to something more sane, which took about three hours of solid uninterrupted work to migrate configuration to a previously unused Cisco 48 port PoE switch (some things are outstanding but I can defer those for another time).

Lastly, I added a new PPPoE connection to the the port already tagging on VLAN ID 2 and viola! I'm connected to the NBN with a device which I have much more trust and configuration options. Even the default firewall rules where reasonable.

Summary

I have learned a few things these last few weeks: how to save some money, how not chase a cable through a wall and not to necessarily jump onto something no matter how exiting it seems and could help with working from home and studying in the future but even more recently, how NBN HFC is delivered and more recently, how important security is with the NBN (more on this in a new post hopefully).

It has been an interesting journey and the thing I enjoyed the most about this was the hardware hacking (however futile it was) and the handyman type work (drilling holes chasing cables etc). What I least enjoyed was the level of service from my RSP and the fact that they managed to bork the username on the account, but all-in-all the actual throughput/bandwidth of the service seems reasonable for now and by the time you read this, I will probably have shut down my ADSL service.

The funniest thing about all this all is the fact that the wife hasn't noticed the improvement in speeds, since I told her (and she agreed) to the experiment of not telling her when it was actually done!

Oh and NBN sent a survey asking about how likely I was to recommend NBN, based on the "excellent" service I received with a scale of 1-10, only to tell me that I had to choose 4 or higher. Go figure.


If you have read this far, thanks for reading and feel free to share your experience with me by posting in the comments or via Google+ (link to post is best).

BIND (named) server remidiation [part 2]

Following up from my previous post (BIND (named) server remidiation), I spent a good couple hours further developing and testing the configuration but failing to get a bind9 reverse lookup zone to load only to find out that I had a slight typo in the reverse lookup zone definition

named-checkzone was returning OK, but named itself was failing to load the zone file with the error:

zone X.X.X.in.addr.arpa/IN: has 0 SOA records
zone X.X.X.in.addr.arpa/IN: has no NS records
zone X.X.X.in.addr.arpa/IN: not loaded due to errors.

It wasn't until I had a friend take a closer look at then the problem became clear:

I defined the zone as .in.addr.arpa instead of .in-addr.arpa in the named.conf include file which references the zone file.

Some things I have learned is:

• Check the logs (in my case, on a default debian/bind9 install this was /var/log/syslog) when things don't work.
• Always check your config with the bind DNS tools before reloading
• Always check your zones files with the bind DNS tools before reloading
• Keep zone files neat and group together similar resource record types.

Now that I have the dev domain DNS working, I just need to look at setting up DHCP and testing dynamic DNS.

I also considered moving different resource records for each zone into a separate file, but this is not necessary, due to the (current) size of the network.

Once this is all done, tested and implemented in 'production', I will also consider keeping a similar configuration in dev as a slave for all zones from the primary DNS or just as it is and just for testing.

BIND (named) server remidiation

Since I virtualised my old failing physical server into a VM, I have found it less and less easy to administer and maintain (read: configuration files).

So, I am looking and spinning up new Debian servers for more specific tasks, network services, games servers, file services etc.

The fist, and most important thing I need to migrate is DNS. That way I can have it simply running in parallel with the old, ready to essentially, stop the service (after making sure DHCP serves out this DNS IP address as well of course!).

Now, here comes the "clever" part or the goals of this approach (or so I thought):

1. Install named.
2. Configure it to be a slave for the existing zones
3. re-configure it to be a master (complete with zone files)

Pretty simple right? Not so much. Well, thanks be to the 'Debian' way of doing things, it was very quick and easy to have a the zones slaved, but when I went to look at the files I was expecting, they where still empty, since I had created empty zone files to begin with.

Some poking around later and I discover that it is transferring the zones fine, but there was an issue with permissions for the zone files, or more specifically, the directory where they lived. A quick chmod -R 0777 /zone/file/directory later and a restart of the service, voila! Except.... something was not right...

The zone files seemed to be in a binary format as file would have me believe they were of type: data

I could have converted them back to plain text using the bind-tool named-compilezone(8) but, I couldn't commit my time to learning how to get the syntax correct for one small job, besides I learned that it is a crazy default in order to get a performance increase, however minuscule that would be given such a small DNS server implementation (for now).

So as per the article "Bind 9.9 – Binary DNS Slave file format" (linked above) or more authoratively as per the Chapter 6. BIND 9 Configuration Reference section of the BIND 9.9 Administrator Reference Manual (ARM) which states (incorrectly):

masterfile-format

Specifies the file format of zone files (see the section called “Additional File Formats”). The default value is text, which is the standard textual representation, except for slave zones, in which the default value is raw. Files in other formats than text are typically expected to be generated by the named-compilezone tool, or dumped by named.

So, knowing this I edited /etc/bind/named.conf.options to include the following:

masterfile-format text;

Perfect. (Just like me ;-) I now have a duplicate of the zones served on the master server, which can, and will soon be decommissioned, not to mention the new servers zones getting a makeover with many many more zones as well as a dynamic-update zone - more to come on this soon.

Great Success

Finally after weeks, no months of agonising failure though trial and error, I finally managed to get the outcome I desired with my Raspberry Pi 2!

History

A few years back I acquired a Cisco 3560 and quickly realised the potential of vlans and separate subnets for the purposes of testing among other valid reasons, and came to find that the nodes on most of the vlans could not communicate with the outside world (read: internet). It was then that I realised that something was wrong...

Long story short: the Netgear DGND4000 that I own does not route/NAT anything other than its resident subnet and I sure as heck was not going to implement double NAT!




Thanks be to LIbVirt's NAT networking which gave me an interim workaround and helped confirm this.

Getting the necessary bits

NAT issues aside, I began by purchasing a second-hand Netgear DM111P v2 from some random guy on Gumtree. The ADSL Modem in itself wasn't enough because it too, seemed to suffer from the same issue as the DGND4000 did, although admittedly, I didn't put much effort into testing that theory as I wanted a solution not more testing.

I then purchased a Raspberry Pi 2 along with a bunch of accessories. In the meantime (while I was waiting the excessively long shipping time). I did some research on the distributions that are capable of running on the bcm2709-based board and decided with OpenWRT. Yes, I know that I could have used Raspbian but OpenWRT seemed the most logical choice given the fact that it is essentially an internet router anyway, just without the wireless and ADSL modem.

Turns out I made the right choice despite the fact that OpenWRT is still in trunk (RC3 at the time of writing this).

Lastly (after destroying the extremely cheap Rpi2 case) I managed to get an image booted (helps when you use the bcm2709 not the bcm2708 barrier breaker version, thats for the Raspberry Model B!).

Configuration

First of all, this would have gone a lot smother had I have just tested with the USB network adapter I bought along with the Pi, but it didn't get here in time with partial shipping.

I configured the switch with a trunk port with two vlans, one for the LAN side of things (internal link) and another for the WAN or pppoe (public/external/internets) and set the mode appropriately.

NOTE: VLANS and IP addresses have been altered so as to protect the actual configuration used in my network infrastructure. Call me paranoid.

Cisco 3650 partial configuration

!
vlan 20
vlan 69
!
interface Vlan69
 description DMZ/LAN
 ip address 192.168.69.1 255.255.255.248
 no shutdown
!
! no interface defined for WAN because we do not want any L3 traffic
!

interface GigabitEthernet0/2
 description Trunk port for Rpi2 VLAN's: 20, 69
 switchport access vlan 69
 switchport trunk encapsulation dot1q
 switchport trunk allowed vlan 20,69
 switchport mode trunk
 no shutdown
!
interface GigabitEthernet0/1
 description Link to DM111Pv2 modem (bridged) for PPPoE/L2 traffic
 switchport access vlan 20

 no shutdown

exit
!
ip route 0.0.0.0 0.0.0.0 192.168.69.66
!
end

OpenWRT network configuration

root@OpenWRT# vi /etc/config/network

config interface 'loopback'
        option ifname 'lo'
        option proto 'static'
        option ipaddr '127.0.0.1'
        option netmask '255.0.0.0'

config interface 'lan'
        option proto 'static'
        option delegate '0'
        option _orig_ifname 'eth0'
        option _orig_bridge 'false'
        option ifname 'eth0.69'
        option ipaddr '192.168.69.66'
        option netmask '255.255.255.248'

config route
        option interface 'lan'
        option target '192.168.0.0'
        option netmask '255.255.0.0'
        option gateway '192.168.69.1'

config interface 'WAN'
        option proto 'pppoe'
        option ifname 'eth0.20'
        option delegate '0'
        option username 'myusername'
        option password 'mY$eCr3tP4sSw0rD'

Caveats/Adendums/Extra information

By now you may be wondering, "Why is there no IP addresses or switch virtual interface for vlan 20"? There is no need for it! That, and the fact one might only want traffic to go via one vlan and then the other (remember, this is essentially a router on a stick implementation and we want to separate the vlan's into L3 traffic for one and L2 for the other per requirements).

If you were thinking: "The netmask and destination network IP for the LAN route is wrong!", you would be incorrect. This is a perfectly legitimate summary route. It allows for much easier (read: slack) administration so one does not have to manage multiple static routes for subnets added or removed from the network (short of running a routing protocol) and it has the added benefit of consuming less memory and is a much more flexible approach for this design. Neat huh? I thought so too :-)

Conclusion

Let it be said that although this configuration is very simple, there where many hurdles accompanied by many choice words along the way. The one single most important thing that I kept getting wrong was routing. I had to remember to change the 'gateway of last resort' (Cisco's way of saying default route) on the switch so that all the subnets will route to the internet and the static (summarised) route for traffic to get back into the network from whence they came. That and trying to test this when the internet is depended upon so much by the two people in this household, was frustrating as my change windows where often short and had to be rolled back constantly.

Lastly, I must say that "out-of-the-box" pppoe/nat/routing on OpenWRT worked with like a charm with minimal configuration, however I will need to develop the scenario a little further so I can secure the connection by way of its firewall (read: iptables), but that itself is a beast I have yet to conquer.

Rasbpberri Pi Internet Connectivity Lab

I have successfully built a lab for testing internet connectivity to the Raspberry Pi 2, by using my phone in a USB tethering configuration.

I followed the majority of the configuration listed in the OpenWRT wiki, except I used the LuCI web configuration instead of the final manual step of using uci to use usb0 as the WAN connection

This will now allow me to test various scenarios including multiple default routes with different metrics as well as testing firewall configurations using OpenWRT running on the Rpi2.

The one gotcha is that I forgot to set the rout back to the internal network for which was previously miss-configured.

I am getting one step closer to having much more control of my internet as well as being able to NET/Route all of my subnets!

failure to focus

I have confirmed that I can get the Raspberry Pi to connect to the ISP using PPPoE through a VLAN, however, I cannot (or rather my brain cannot) get the OpenWrt to accept traffic other then ICMP to/from the device itself (I probably need to understand iptables or I am overlooking something very simple).

I'm finding it extremely hard to focus and get the networking part of this lab working right now when I don't actually have a lab to do it on and when others in the household rely on internet so much including myself, when I need to refer to something while trying to troubleshoot and find a solution to this 'router-on-a-stick' model of networking to overcome the shortfall of the existing router.

I've also lost my 4Gb micro SD for which I was planning using for building a Bluetooth (A2DP) Audio receiver from the Raspberri Pi which is making me a little less than happy considering they are not as easy to come by due to the size and I will have to spend another $10 (effectively $20 now) in order to get one.

For now, I'm going to go watch something and try again later (including looking for the SD card).

Google Plus killed the technology blog

This may be the final entry in this and my other blogs.

I managed to painstakingly avoid using Facebook for many years, and instead waited patiently for Google to create it's social networking site, Google Plus (If you have never heard of Google+, I strongly urge you to go back to the rock you have so obviously been living under and/or go read some other non-technical site).

Ever since I have been active on Google+ (since soon after it's initial Beta period), have found it to be absolutely brilliant, if not addictive, and a far better medium to which I can expose my technical knowledge and findings to the masses.

This means that there is little or no time for the blog and I am almost positively confident of using one or more Google+ page(s) to replace this and most probably all of my other blogs.

Thank you Blogger for your great blogging service, but thank you so much more Google plus for finally giveing me what I (and so many other Google fans) wanted.