We have a deployment of phones that are in people’s homes of Yealink T20 and W52P phones. They all use different routers and ISPs. As a result of port scanning they are getting calls from “100” or “200”. yealink had a fix on their phones but it does not seem to be working anymore. Has anyone found a way to stop these at the router since they are not coming through the PBX.
Tell the yealinks to use a different “local” port. And no I do not mean a different port on your server. You see the yealinks are stupid and they will use the local port of “5060” (I have not found another phone that does this) to connect to your server’s “5060” instead of randomizing the port (like other manufacturers do), thereby making your users’ routers open up 5060 as inbound…
The setting you are looking to change is called “Local SIP Port”. I found it under Account > Advanced > “Local SIP Port”. It can be anything really. Just go higher up. Again, you don’t have to change anything server side or even router side.