VoIP / SIP Voice Issues with Nagios

[falawlen]

i think the size of your nagios server is irrelevant here.

At the time, the info about it being a VPS was not posted. I was thinking maybe the entire network was having issues. I mostly agree with the above at this point, though I am still curious about how the PBX network is setup. Like, are all the phones on the same network?

It seems to me the real issue is why is the phone system not responding? The network may have high non-nagios related traffic at those times.

Are you monitoring bandwidth on the Nagios server? That could tell us if it's something coming from the server, whether ping or not.

Thanks for everyone's reply. I'm going to enable the Nagios server again this weekend to see if I notice any bandwidth issues. I'm also going to run a few packet captures as well and share them as I get them this weekend.

The issue was never that the phone system was not responding, it was being monitored just fine. While being monitored is when the issues occur and the only way I knew this was happening was because a client called me.

Here is the network in a nutshell;

ISP -----------------------> WAN PfSense
LAN PfSense -------------> Cisco SG300 PoE
Cisco SG300 PoE ---------> (4) VoIP Phones, PBX System

Nagios is pinging the WAN interface on the PfSense
Nagios and the PfSense are not on the same network

I'm sure its just a setting in Nagios that I need to find. I think the packet captures will tell the real story on this one.

[eloyd]

Packet captures will definitely tell you the story. 4 phones on a PBX shouldn't have any issues with a normal Nagios service check. We have dozens of PBXs with hundreds of phones each with zero problems being monitored by Nagios.

[dwhitfield]

I have Nagios setup to Ping every 5 mins and then if it doesn't respond to try again every min for 4 times. With this setting, it would cause issues with the voice quality on the SIP Phone System.

Based on the above quote, and your most recent post, you are saying that the ping every 5 minutes is where you are seeing these issues, correct?

[falawlen]

I have Nagios setup to Ping every 5 mins and then if it doesn't respond to try again every min for 4 times. With this setting, it would cause issues with the voice quality on the SIP Phone System.

Based on the above quote, and your most recent post, you are saying that the ping every 5 minutes is where you are seeing these issues, correct?

Yes, those were the settings. Unfortunately, I do not know how often or the times. Once I re-enable Nagios, I'll be able to get more info with the packet captures and the times. All I know at this time is that when Nagios is running it was causing the issues. Which doesn't make sense to me since its just a ping. It would make sense if it was pinging more often like a DDoS attack but I don't see any configurations when I was looking through it. I'll triple check everything when I start the packet captures.

[dwhitfield]

I'm still a little confused about whether it was pinging every five minutes or every minute. If they never went down, then it would be 5 minutes, but your comment about not being sure means...you aren't sure if Nagios was saying they were down? Regardless, it shouldn't matter unless there is an absolutely massive amount of checks, which there isn't.

Let us know when you get the packet captures!

[eloyd]

Also, the rather small size of the VoIP deployment makes me think that something weird is going on at the network level, and the Nagios checks are simply exposing it. Packet captures and other low-level network diagnostics will be very useful.

[dwhitfield]

Also, the rather small size of the VoIP deployment makes me think that something weird is going on at the network level, and the Nagios checks are simply exposing it. Packet captures and other low-level network diagnostics will be very useful.

All excellent points! Thanks @eloyd.