Hi all,
At my office I successfully replaced our provider's router with a hex S. I managed to port also the VoIP service, but the IP phone they provided us works by sending keepalive approximately every 10 minutes, hence a smaller UDP timeout in the NAT tracking would render inbound calls impossible.
Effectively, I managed to inspect the previous router's config and the timeout for NAT UDP connection tracking was set to 11 minutes.
I have changed the default setting in RouterOS for UDP stream timeout and the phone works fine, however I was wondering if there was a finer-grained setting that could apply a different timeout based on LAN IP/VLAN (I have the feeling the previous router could do this based on reverse-engineering the config). I wouldn't like to change such a setting from the default of 3 mins. to 11 and having the connection table grow hugely in size as a consequence.
Also, what could be a different approach? DST-NAT on the SIP port towards the LAN phone IP, but that would mean dedicating port 5060 exclusively to that phone and preventing the possibility of, for example, using a softphone on a different host?
Thank you