Polycom Audio not working behind NAT

nohungry381 · November 4, 2021, 4:44am

Dear Everyone,
I’m a network engineer working for a ISP on SEA Area.
We are deploying vpn connection and Online conference for customers.
Everything work fine with low cost router, when I just disable SIP ALG, but when i use mikrotik hex s and intergrated PPPoE and VPN connection, the conference connect via internet OK but via VPN not work.
I configure L3 VPN on Mikrotik Router, and client is laptop install polycom realpresence desktop. When I configured mode bridge, and Public IP address on Laptop it work fine.
I attached the configuration file at this email.

Pls help.
Thank.
polycom_mikrotik_config.rsc (4.69 KB)

nohungry381 · November 25, 2021, 4:03am

I check sip packet, althought I turn on or turn off sip service (IP → Firewall → Service) the local IP address not change to WAN IP

flasix · November 30, 2021, 2:57pm

Some setting need to be reviewed … but quickly here’s some tracks to check: almost of your interfaces belong to the WAN list. Firewall Filter Rules and masquerade are actually “dropping” some connections NOT from LAN interfaces list.
If the RealPresence server is behind you’re hex s > recheck the firewalls to deal with LAN connections. Considering Hairpin NAT eventually.
If the RealPresence server is in the cloud, review the routing table (0.0.0.0/0 ?).