James Batchelor – Page 2 – Useful I.T & VoIP Ramblings

Manually install net-snmpd on Gentoo

Recently we’ve moved from an aged Opsview instance to Zabbix for our system health monitoring, which in turn facilitated moving data collector agents from Nagios to snmp.

Many of our PBX’s were deployed from the vendors ISO and so run atop of Gentoo, and it has a couple of issues:

We’ve been told not to “emerge” anything by the vendor, as the base OS on the image is not maintained.
Portage (Gentoo’s package manager) has fallen out of date, meaning even if emerge is attempted, it’ll fail as all repository links are broke.

If faced with the same issue, this is how to install net-snmpd from source, add it a startup service and be able to monitor via snmp…

POE Cooling A POE Switch

For years I’ve been searching for a passively cooled 16-24 port L2 managed POE switch to replace a Cisco SG110-16HP unmanaged POE switch. Seemingly impossible, the need to play with VLANs made me give up on this search and ended up buying a Netgear GS324TP.

The main compromise in choosing this was that it offered “near silent” operation by only spinning the fans when needed, compared to other switches where fans are on permanently.

Trouble is, when the fans do spin on the GS324TP they are audibly intrusive, whether brand new or a few months in they sound like the bearings are failing with a knock that matches the RPM, deploying four of these units previously with the same harmonics suggest it’s not a one off.

This isn’t good news when I intend to work a few feet from the switch, but from testing before the latest deployment, there’s a couple of ways to keep the GS324TP near silent…

iDRAC 6: Remote Console

A few months ago a freshly retired Dell Poweredge T310 came back to the office, I plugged it into the network and left it off in the unlikely event it data was needed off it. It’s now I’m remote to the office, and need it’s data.

No problem I thought, use the iDrac to log into the ESXi console and set a new IP as it is statically assigned to a different subnet to the office…

Trouble is, the iDrac is so out of date I can’t get to its web interface on any browser available to my Windows 10 machine.

This is how to get access to an outdated iDrac 6 web interface and remote console…

Yealink OpenVPN to Draytek Router

The firewalls in front of our PBX’s are configured to only allow SIP traffic from UK IP addresses, this reduces the attack surface and is usually not an issue as almost all legitimate traffic is from the UK.

As we expand there is greater need for international connections, this is fine if they have a static WAN IP or FQDN, but the more recent requirements are for “home” users with phones on their residential connections where dynamic IPs are the standard.

Changing the whitelisted IP every time their IP changes is not only tedious, but gives poor service, plus due to recent events (here and here) I’m not prepared to open access to another country for a single extension.

In my case, these internationals are satellites of a UK based office, so the idea is having the overseas phone route all voice traffic through the UK office where its free to connect to the PBX…

WiFi: Draytek 2927ac WiFi vs Unifi NanoHD

A Draytek, be it a 2765, 2865, or 2927 based on WAN connectivity and LAN complexity is my go to device for a router. More than likely these are the ‘ac’ variants as WiFi provision is expected rather than featured.

In newer Draytek models the perceived performance of wireless as been lacking based on earlier models such as the rock solid 2860n/plus with reduced range and throughput speeds, in particular poor VoIP performance for my industry.

This could be down to the passage of time and how WiFI has become even more ubiquitous, in demand and ultimately a more congested radio band. Regardless an alternative solution needs to be explored.

Previous dabbling with deployment of Unifi access points have yielded trouble fee results, so this would be a quick win. Trouble is, the default AC-Pro and AC-LR are in serious supply shortages at present. Wifi 6 variants have better stock availability but also have a higher purchase cost.

The only Unifi AC product that is plentiful is the NanoHD, so in desperation lets see if it is a justifiable upgrade to the Draytek offering…

Add Unifi Controller to CentOS 7

I’m in the process of testing a Unifi AP (Nano), and need a controller to set it up. As its a temporary setup I choose the old faithful CentOS 7…

Increase disk size on Gentoo VM Instance

There are occasions when the storage capacity of a virtual drive needs to be increased. In production environments a backup and re-install of an OS to a higher capacity provision may not be practical.

Many of our systems deployed from OVA’s use Gentoo as it’s base OS for inexplicable reasons, here’s how to increase the drive capacity of a VM instance running Gentoo and make the extra space usable…

Provisioning Polycom Phone

Yealink is our go to vendor for telephony hardware, mainly due to its ease and variety of configurability. But recently have been tasked with adding a Polycom VVX250 to the system for a charity to use.

While the setup between different manufacturers normally follows the same general path. This is a journey of how Polycom interprets it…

NordVPN / Draytek 2862 LAN to LAN Not Connecting

I’ve been a NordVPN customer for about 6 months now, mainly due to its ongoing support of L2TP connections. However recent changes to its service put my use of this service with my Draytek 2862 in jeopardy. Luckily there is a fix, and it’s a story of updates…

Provisioning a Cisco 7940/7960

2021 is here and so returns (In the UK at least) one of my favourite shows to Netflix, The Office (US). Since starting working in VoIP its hard not to notice what phones turn up in TV shows, here the Cisco 7960, was prolific for showing up in shows around this era.

So why not, nearly 16 years after the show started, try and get one of these working on an Asterisk PBX? At work we had a number of similar 7940 models that hadn’t be used for years, so why not give it a try…