How to disable SIP Alg when Telnet access is denied? Please? (VOIP Router)

[Christiane74]

Hi,

I encounter issues with voip calls for years and my voip provider always signals that sip alg is still enabled.

I found the command line :

no ip nat service sip tcp port 5060
no ip nat service sip udp port 5060

BUT I can't accès the device through Telnet (accès denied) and not even through putty (accès denied as well).

How can I finally get rid of the sip alg, please? After years of dysfunctioning calls.

Thanks

I own 2 Voip routers WRP400

[AnthonySylvester]

Are you able to access the device any other way? You will need to login to the device (physically or remotely) to make config changes.

Here is the link to the WRP400 Admin Guide:

https://www.cisco.com/c/dam/en/us/td/docs/voice_ip_comm/csbpvga/wrp400/administration/guide/WRP400_AG_OL-19688.pdf

[Christiane74]

Hi
Thanks for answering my question.
Sure I can access the device with my admin password. But that doesn't let
me disable le sip alg.
I have problems for years now with my voip and nobody can tell me how to
get rid of the sip alg.
Can you help me with this?

[AnthonySylvester]

Hey Christiane74,

After doing some more research, it looks like the WRP400 is End-of-Sale and End-of-Life as of 2014/2015. Just wanted to make sure you were aware of that.

https://www.cisco.com/c/en/us/products/collateral/unified-communications/small-business-voice-gateways-ata/eos-eol-notice-c51-733176.html

Also, the data sheet for the WRP400 has no mention of the SIP ALG feature.

https://www.cisco.com/c/en/us/products/collateral/unified-communications/wrp400-wireless-g-broadband-router-2-phone-ports/data_sheet_c78-502141.html

Here is an excerpt from the WRP400 Admin Guide that could potentially help:

To enable SIP requests and responses to be exchanged with the SIP proxy at the ITSP, you must ensure that your firewall allows both SIP and RTP unimpeded access to the Internet.
• Make sure that the following ports are not blocked:
     • SIP ports—UDP port 5060 through 5063, which are used for the ITSP line interfaces
     • RTP ports—16384 to 16482
• Also disable SPI (Stateful Packet Inspection) if this function exists on your firewall.

Bottom of Page 26 - Top of Page 27:

https://www.cisco.com/c/dam/en/us/td/docs/voice_ip_comm/csbpvga/wrp400/administration/guide/WRP400_AG_OL-19688.pdf

Additionally, I would suggest reaching out to your voip provider and ask them what the sip messages they're receiving look like, and what they are expecting. Once you know what they're expecting, you could potentially do more testing until packet captures on your egress interface towards the voip provider meet their criteria.

Hope all this helps.