Cisco CME - SIP Providers

Some SIP providers require that your PBX use a specific SOURCE port when communicating with their network. Voip Your Life (VYL Media) business setup authenticates via public IP address and requires that your PBX use port 5060 as a source and destination port when communicating with their network.

The problem is that by default, Cisco CME does not use a static source port; it uses a random unassigned source port. This resulted in outgoing calls not working. Their device was specifically responding with a 404 not found error (which is not very helpful). To get this to work properly, we had to configure the UC540 to use port 5060 for the source port.

conf t
sip-ua
  connection-reuse
end

Additional information from Cisco:

1. By default the source port for SIP messages that the UC500 sends is ephemeral or random which is per the spec. You can force this to always be UDP 5060 by looking at section 4.4.12 on guide below

https://www.myciscocommunity.com/docs/DOC-1560
If the provider requires that SIP traffic always be sourced from the UC520 using TCP or UDP port 5060, this can be changed at a system level as below:
sip-ua
  connection-reuse

2. Need "deb ccsip message" for this to check the reason for the error. One possibility is mentioned here:
https://www.myciscocommunity.com/docs/DOC-1520#Inbound_calls_from_SIP_Trunk_on_UC520_fail_when_configured_using_CCA_19_or_higher

Earlier posts on NexVortex:
https://www.myciscocommunity.com/message/5595#5595