[SR-Users] How to hide Via and Record-Route header to external network and restore them to internal network?

Fri Sep 2 10:02:31 CEST 2022

Hello,

As you can see in the trace, SIP request from uac pass through several nodes before reaching the SBC.
So when the SBC send back the reply inside my network, there is no more Via and route-record headers and the adjacent node is not able to route the SIP reply to the uac.
Regards,

Anthony
________________________________
De : Henning Westerholt <hw at gilawa.com>
Envoyé : vendredi 2 septembre 2022 09:44
À : Anthony Blandin <anthony.blandin at airnity.com>; Kamailio (SER) - Users Mailing List <sr-users at lists.kamailio.org>
Objet : RE: How to hide Via and Record-Route header to external network and restore them to internal network?

Hello,

as mentioned, this is not the way the module works. I will just not differ between internal and external.

Why you need the topology information on the inside?

Cheers,

Henning

--

Henning Westerholt – https://skalatan.de/blog/

Kamailio services – https://gilawa.com<https://gilawa.com/>

From: Anthony Blandin <anthony.blandin at airnity.com>
Sent: Thursday, September 1, 2022 3:26 PM
To: Henning Westerholt <hw at gilawa.com>; Kamailio (SER) - Users Mailing List <sr-users at lists.kamailio.org>
Subject: RE: How to hide Via and Record-Route header to external network and restore them to internal network?

Hello,

I tried topoh and topology hiding is working well towards the external network but it does not restore the Via and Record-Route on the replies.

Maybe I miss something in the configuration, I attached a pcap file if you can help me.

What I want is to restore all the Via and Record-Route headers from the incoming INVITE to the Session Progress returned back to the previous node.

Thanks

Anthony

________________________________

De : Henning Westerholt <hw at gilawa.com<mailto:hw at gilawa.com>>
Envoyé : jeudi 1 septembre 2022 12:14
À : Anthony Blandin <anthony.blandin at airnity.com<mailto:anthony.blandin at airnity.com>>; Kamailio (SER) - Users Mailing List <sr-users at lists.kamailio.org<mailto:sr-users at lists.kamailio.org>>
Objet : RE: How to hide Via and Record-Route header to external network and restore them to internal network?

Hello,

the topology hiding is applied to both sides, so the modules not care. You can control execution with parameters and also some event route, depending on the module and Kamailio version.

Just note if you want the headers to really removed from the message, consider using topos with a SQL DB or redis.

Cheers,

Henning

--

Henning Westerholt – https://skalatan.de/blog/

Kamailio services – https://gilawa.com<https://gilawa.com/>

From: Anthony Blandin <anthony.blandin at airnity.com<mailto:anthony.blandin at airnity.com>>
Sent: Thursday, September 1, 2022 11:42 AM
To: Henning Westerholt <hw at gilawa.com<mailto:hw at gilawa.com>>; Kamailio (SER) - Users Mailing List <sr-users at lists.kamailio.org<mailto:sr-users at lists.kamailio.org>>
Subject: RE: How to hide Via and Record-Route header to external network and restore them to internal network?

Thanks Henning.

I will try it.

How topoh determines that it is a SIP message to be sent outside my network or not?

Anthony

________________________________

De : Henning Westerholt <hw at gilawa.com<mailto:hw at gilawa.com>>
Envoyé : jeudi 1 septembre 2022 11:16
À : Anthony Blandin <anthony.blandin at airnity.com<mailto:anthony.blandin at airnity.com>>; Kamailio (SER) - Users Mailing List <sr-users at lists.kamailio.org<mailto:sr-users at lists.kamailio.org>>
Objet : RE: How to hide Via and Record-Route header to external network and restore them to internal network?

Vous ne recevez pas souvent de courriers de la part de hw at gilawa.com<mailto:hw at gilawa.com>. Découvrez pourquoi cela est important<https://aka.ms/LearnAboutSenderIdentification>

Hi Anthony,

the restore happens internally and in the configuration you are able to access the headers, this is transparent for you.

Just give it a try in your lab, you can easily see it on the network.

Cheers,

Henning

--

Henning Westerholt – https://skalatan.de/blog/

Kamailio services – https://gilawa.com<https://gilawa.com/>

From: Anthony Blandin <anthony.blandin at airnity.com<mailto:anthony.blandin at airnity.com>>
Sent: Thursday, September 1, 2022 11:08 AM
To: Henning Westerholt <hw at gilawa.com<mailto:hw at gilawa.com>>; Kamailio (SER) - Users Mailing List <sr-users at lists.kamailio.org<mailto:sr-users at lists.kamailio.org>>
Subject: RE: How to hide Via and Record-Route header to external network and restore them to internal network?

Hi Henning,

Yes, I looked to topoh to hide topology but I didn't find a way to restore back the Via and Record-Route headers when I get replies from the external network.

Regards,

Anthony

________________________________

De : Henning Westerholt <hw at gilawa.com<mailto:hw at gilawa.com>>
Envoyé : jeudi 1 septembre 2022 11:01
À : Kamailio (SER) - Users Mailing List <sr-users at lists.kamailio.org<mailto:sr-users at lists.kamailio.org>>
Cc : Anthony Blandin <anthony.blandin at airnity.com<mailto:anthony.blandin at airnity.com>>
Objet : RE: How to hide Via and Record-Route header to external network and restore them to internal network?

Vous ne recevez pas souvent de courriers de la part de hw at gilawa.com<mailto:hw at gilawa.com>. Découvrez pourquoi cela est important<https://aka.ms/LearnAboutSenderIdentification>

Hello,

already investigated the topology hiding modules (topos, topoh)? They might be not doing exactly what you are describing, but usually are used for this kind of scenarios.

Cheers,

Henning

--

Henning Westerholt – https://skalatan.de/blog/

Kamailio services – https://gilawa.com<https://gilawa.com/>

From: sr-users <sr-users-bounces at lists.kamailio.org<mailto:sr-users-bounces at lists.kamailio.org>> On Behalf Of Anthony Blandin
Sent: Thursday, September 1, 2022 10:58 AM
To: sr-users at lists.kamailio.org<mailto:sr-users at lists.kamailio.org>
Subject: [SR-Users] How to hide Via and Record-Route header to external network and restore them to internal network?

Hi Community,

I have set up a SBC with Kamailio.

I am testing voice call from external network to my network and voice call from my network to external network.

When I send SIP messages to external network, I want to hide Via and Record-Route headers but when I receive replies from the external network I want to restore these Via and Record-Route headers to my network.

How to store and restore these headers in Kamailio configuration ?

Could you help on this?

Thanks

Anthony Blandin

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