I have worked in the VoIP industry for quite a while and I am a little stumped on something I have noticed recently.
I administer a number of SIP based servers such as Asterisk, FreePBX, 3CX etc. Normally when a home users has a phone at his/her home behind their home router NAT device, the source port of the phone is different from the actual source port on the phone.
In very rare cases I see the source port exposed on the public interface as the same as the port on the phone (usually...
NAT routers exposing real source port of device behind NAT
I administer a number of SIP based servers such as Asterisk, FreePBX, 3CX etc. Normally when a home users has a phone at his/her home behind their home router NAT device, the source port of the phone is different from the actual source port on the phone.
In very rare cases I see the source port exposed on the public interface as the same as the port on the phone (usually...
NAT routers exposing real source port of device behind NAT