[Asterisk-Users] SIP UDP ports on firewal to open

[Rich Adamson]

> I notice most things say to open ports 10000-20000 for UDP for SIP,
> however from time to time this range isn't where Asterisk is opening the
> ports:
> 
> We're at xxx.xxx.xxx.xxx port 8542
> Answering with capability 0x2(GSM)
> Answering with capability 0x4(ULAW)
> Answering with capability 0x8(ALAW)
> 
> This call has no audio, presumably because port 8542 is firewalled in
> the iptables on the server.
> 
> Is there somewhere I'm missing to port a port range in sip.conf
> (shouldn't there be if there isn't?).

Each sip device (including *) has a udp port range set by the OEM.
For *, take a look at rtp.conf and you'll see 10,000 to 20,000.

For Cisco phones, look in SIPDefault.cnf and you'll see they use
16,384 to 32,766.

So, data flows from * to Cisco might use udp 10,123 but Cisco to *
might use 31,123 for rtp flows.

Unless you change the port range for every sip phone coming through
your firewall to some consistent range, expect to see whatever the
OEM decided to use for their product.