Mikrotik RouterOS - incorrect SNMP status for idle WLAN interfaces

Posted on Sun 07 January 2018 in Tech • Tagged with Tech

While trying to monitor the status of one of our wireless access points, I discovered that RouterOS returns an incorrect SNMP status code for the wlan interfaces when there are no clients connected to the interface. This is at least present in RouterOS v6.40.3, on a Mikrotik cAPlite (RBcAPL-2nD).

Specifically, when the wifi interface is up, but has zero connected clients, the OID returns an SNMP value of 2 ("down"). This status is incorrect - the interface isn't down, it's merely waiting for an external connection.

The specific OID …


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When the problem is DNS: FreeNAS and NFS

Posted on Sun 07 January 2018 in Tech • Tagged with Tech, Linux

I discovered a while ago that NFS requires DNS to function correctly: https://bugs.freenas.org/issues/4983

That's somewhat annoying, because when your DNS server goes down (and your backups are stored on your FreeNAS server and accessed over NFS), is precisely the time when you really want your backups to be accessible.

However, turns out it doesn't aaaaactuallyyyyy need DNS... it needs name resolution. Specifically, FreeNAS just needs to be able to resolve it's own hostname. Cue the handy-dandy hosts file.

Under Network -> Global Configuration -> Host name data …


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Flashing a Samsung S5 G900I back to stock

Posted on Tue 19 December 2017 in Tech • Tagged with Android, Tech

I got a second-hand Samsung Galaxy S5 for my mum yesterday (a G900I model, from Telstra), and I spent some time getting it ready.

Firstly, I downloaded the most-recent Telstra firmware image. At time of writing, that's G900IDVU1CQJ2. Telstra appears to be the only carrier still releasing stock firmware for this phone, so I downloaded the Telstra version even though we're connecting to Spark New Zealand. This means the phone will at least be running the most up-to-date baseband and modem firmware.

Note - if you try this, and find that …


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Making MindTouch's Dekiwiki work on Debian Stretch

Posted on Sun 17 September 2017 in Tech • Tagged with Tech, Security, Linux

We had accumulated a certain amount of technical debt, due to a Wiki solution that was selected a few years ago: Dekiwiki, by MindTouch. Unfortunately a few months after implementation, MindTouch Core (which Dekiwiki builds on) was well-and-truly deprecated back in 2013.

It all happened before my time, but it seems as if Dekiwiki came as a pre-built VMware Appliance, based on Debian Etch (Debian 4.0; released in 2007). After giving our Dekiwiki environment some serious side-eye for a while, I finally decided to get my hands dirty and …


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Compiling Heimdall without installing Qt

Posted on Wed 13 September 2017 in Tech • Tagged with Android, Tech, Linux

During my recent Wrecked-phone Saga, I had some trouble flashing my firmware. My phone was broken at the time, so I couldn't enable ADB Debugging - therefore adb wasn't an option. OEM Bootlock was on, so fastboot wasn't an option. My Recovery bootloader was also broken. I thought my phone was bricked.

That's until I remembered Heimdall.

Heimdall is specifically a tool for working with the partitions on Samsung phones - other visitors need not apply. It works a treat for my Samsung Galaxy S5 (kltedv) though.

Heimdall, however, is old. The …


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When Encryption Attacks!

Posted on Tue 12 September 2017 in Tech • Tagged with Android, Tech

So... I wrecked my phone last night. :-(

Android's phone encryption feature has been around for aaaages, so I was confident when I started the encryption process last night. Unfortunately, something went wrong, and last night I discovered that everything was toast.

After a bit of digging, I found someone else with exactly the same problem!

"unable to boot into my phone as it sits at the boot screen. When I try to boot into TWRP, it asks for my password. [...] it appears to decrypt the partition and mount, but then …


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Firmware update on an APC AP9630 NMC2

Posted on Sat 02 September 2017 in Tech • Tagged with Tech

I've spent a little while working with the APC Network Management Cards now, and firmware updates are a total pain.

The biggest issue is that the UPS power outlets need to be powered off in order to flash the firmware, otherwise there's a terrifyingly-high chance that the NMC (a ~$700 card) will completely shit itself, and die permanently. Aside from that, I've never managed to get updates working properly from the web interface.

Fortunately, the card is hot-pluggable, so if you have a spare UPS hanging around, you can unplug …


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Respecting Amavis' "Banned Extensions" setting

Posted on Sun 13 August 2017 in Tech • Tagged with Tech, Security, Linux, Mail

I've been dabbling a little bit with iRedMail, mostly just to have a play with a mail server, but also to see what's involved in mail security. iRedMail is a package that pulls together Postfix as an MTA, Dovecot as a POP3 & IMAP server, SOGo for ActiveSync, Roundcube for Webmail, SpamAssassin for spam protection, and ClamAV for virus scanning.

Okay I have no idea why I have to write this, but apparently it's a thing.

Amavis has a list of banned file extensions. In Debian, they live in /etc/amavis …


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Tuna Patties

Posted on Sun 13 August 2017 in Food • Tagged with Recipes, Food

What do you do when it's dinner time, and you haven't got any ingredients ready for the meal?

What if (perhaps as a result of being an ultralight hiker), you also have a huge surplus 500g sachet of tuna?

Tonight these particular stars aligned, and I ended up making these amazing Tuna Patties: http://allrecipes.com.au/recipe/15705/tuna-patties.aspx

I did tweak the recipe considerably, though:

Ingredients:

  • 2-3 large potatoes, peeled and cubed for mashing
  • Optionally, swap one of the potatoes for a kumara or some pumpkin
  • 500g …

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Making Amavis work with ESET Antivirus

Posted on Sat 12 August 2017 in Tech • Tagged with Tech, Security, Linux, Mail

I've been dabbling a little bit with iRedMail, mostly just to have a play with a mail server, but also to see what's involved in mail security. iRedMail is a package that pulls together Postfix as an MTA, Dovecot as a POP3 & IMAP server, SOGo for ActiveSync, Roundcube for Webmail, SpamAssassin for spam protection, and ClamAV for virus scanning.

But of course, ClamAV has shown disappointing performance, and it would be really nice to use something more... commercially suitable.

To tie together mail receipt and scanning, iRedMail uses Amavis (strictly …


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