MTU on multiple model cameras

[bau55536]

Good morning!

We've had an ongoing issue with our Avigilon NVRs and Axis cameras at two remote sites, connected via VPN tunnel over internet circuits. Avigilon logs complain about packet drops and in troubleshooting another unrelated issue, Avigilon tells is we need to fix our network issues as they're what are causing the issue...(they're not, the issue is reproduceable on the same local network, but I digress.) All the logs for lost packets are at our two remote sites.

In this case, we see that there are packets dropped when they're over the MTU size of the VPN tunnel (1420) and we're fairly certain these are the packets that the NVR is reporting as missing as well. In looking at packet capture, I see that the camera is setting the do not fragment flag, so we believe anything over 1420 is dropped at the firewall. As I don't see any way to set MTU in the web interface, I've been delving into cli access via ssh. Trying to find the actual network configuration files to see if MTU is configurable there, as the camera won't let me change the MTU dynamically.

Thanks in advance for any advice. Not sure if this belongs in one of the other forums, so I figured to start here.

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[vivekatoffice]

Hi @bau55536 ,
I have never used it, but you can set the MTU using Plain config --> Network option:

VAPIX API for the same is following:

Method: GET
URL: http://195.60.68.14/axis-cgi/param.cgi?action=update&root.Network.Interface.I0.Link.MTU=1300
Response: OK