Cisco CUCM source port of SIP-trunk

DOM.RF NOC · ‎01-20-2016

Hi, everybody!

Which port or port-range does CUCM use for SIP-trunk source port? Is it the ephemeral port range 32768 – 61000?

Rajan · ‎01-21-2016

Hi Filipp,

SIP trunk communication normally uses port 5060. If you mean the ports advertised by the endpoints for media communication in SDP, then it will be in RTP port range 16,384 - 32,767.

HTH

Rajan

DOM.RF NOC · ‎01-21-2016

No, i mean which source port use CUCM for outgoing SIP-trunk messages?

Vivek Batra · ‎01-21-2016

Hi,

Rajan has already replied, it will use 5060 by default.

- Vivek

DOM.RF NOC · ‎01-21-2016

As i see on my router access-list matches it is use something like this for SIP tcp source-port: 52202

Rajan · ‎01-21-2016

Can you check whether "Incoming Port" option in the SIP trunk security profile configuration in CUCM to see whether it has been modified to use any other port other than the default 5060.

http://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/security/9_1_1/secugd/CUCM_BK_C0395F44_00_cucm-security-guide-91/CUCM_BK_C0395F44_00_cucm-security-guide-91_chapter_011001.html#CUCM_RF_SF74AEF0_00

Thanks,

Rajan

Vivek Batra · ‎01-21-2016

Ohhk... if you check SIP over UDP, you will see the port as 5060. When use TCP, although SIP process still using and running on 5060, but TCP layer assigns dynamic port while sending packet to lower layer, that is usual with any application using TCP. Inside the SIP TCP packets, you will still see 5060 being used.

- Vivek

Ayodeji Okanlawon · ‎01-21-2016

Vivek,

SIP over UDP also uses different UDP ports other than 5060. 5060 or 5061 is for sip but UDP as a different tramnpsort protocol uses its own dynamic port

Please rate all useful posts

Vivek Batra · ‎01-21-2016

Hi Deji,

Yes, SIP over UDP can use any valid port besides 5060, that's why I mentioned before that it is by default. However behavior of UDP is different from TCP with respect to SIP usage.

With SIP over UDP, it is in control of application (implementation dependent) itself whether to use static or dynamic port. Like many SIP server applications only support static UDP port for SIP, but some other client applications (like Xlite softphone) can be configured to use dynamic UDP ports range.

With TCP, it is not in control of application (at least I've not seen). Whatever SIP port is used by application whether it is 5060 or other, TCP layer will assign random port in the TCP header and probably SIP application is not aware about this port.

My two cents :)

- Vivek

Ayodeji Okanlawon · ‎01-21-2016

Yes this is indeed correct. You need to remember sip as a signalling protocol needs a transport mechanism. This can be either TCP, UDP or TLS over TCP. The port you see here is the TCP port used to carry the sip signalling messages.

Look at the wireshark trace below..You will see something similar. In this case we use UDP for our transport and you can see my UDP port is 59473..

Please rate all useful posts

egbekunlego · ‎01-26-2018

Hi Vivek/Deji,
Thanks for your wonderful contributions. I think both of you are saying same thing. Vivek mention that the implementer can decide to use static port or dynamic port numbers for SIP calls over UDP and same thing Ayodeji showed in the .pcap message flow of static ports (59473 or 53390) used for the different transactions of the calls. I stand to be corrected if I'm wrong. And also I will like to know where to define to use static port on cisco voice routers and how to modify from using another value apart from the default 5060; say 59473 as in Deji's message flow. Thanks

Chidu · ‎03-29-2023

hi all, i know this is old post however i am looking at associated issue i am facing here. we in the process of building SIP trunk however the SIP service provider is not accepting the traffic as SIP invite is not going to them with port details.our SIP service provider says at the end of IP in the 'From' field it should carry the port 5060 . however we have tried multiple things on the AudioCodes SBC no luck with that. we can manipulate SIP Invite messages on the CUCM side ?

Roger Kallberg · ‎03-29-2023

Please create your own post to ask your question as it's totally off topic to the OP question. What you're asking about is a SIP trunk from an SBC and what the OP asked about is source port on a SIP trunk from CM. Not even remotely the same.