it looks like you are handling contact manually but also call "fix_nated_contact/add_contact_alias" function as well. 
You can't call 2 functions for the same header - it breaks the logic of how kamailio deals with the config at the postprocessing. 
There are 2 ways to fix it:
- remove nat helper functions touching contact ( preferred as you don't need it anymore for the INVITE flow )
- use msg_apply_changes after the first function (which I would not recommend as it rereads the message again and defacto Kamailio parses the same message twice )

However as Alex Balashow mentioned - this is a really bad approach - to rewrite contact on the proxy, and it has to be used for corner cases and you are not at one of them.
You have to deal with Record-Route/Route headers to be able to manage the routing.


чт, 4 авг. 2022 г. в 07:30, Ankit Jayswal <ankit.jayswal@engagely.ai>:
Yes,
When I use remove_hf() and insert_hf() it doesn't remove the value of the Contact header properly.

Below code executed:
remove_hf("Contact");
insert_hf("Contact: <sip:00912269240500@10.52.26.98:5060>\r\n", "Contact");


I have given the sngrep INVITE request below after applying the above code. See the highlighted contact header not removing previous value properly.

contact_header.png




On Wed, Aug 3, 2022 at 8:30 PM Alex Balashov <abalashov@evaristesys.com> wrote:
How did you conclude that it doesn’t work?

> On Aug 3, 2022, at 8:06 AM, Ankit Jayswal <ankit.jayswal@engagely.ai> wrote:
>
> Hello,
>
> Can you suggest directly replacing the value of the Contact header ? As remove_hf("Contact") does not work for me.
>
> I need just Contact: <sip:009122692405xx@10.52.26.98:5060> instead of,
> Contact: <sip:0091692405xx@45.118.162.x:5080;alias=10.52.26.102~5080~1>
>
>
> On Tue, Aug 2, 2022 at 12:56 PM Alex Balashov <abalashov@evaristesys.com> wrote:
> The suggestion given by Henning was to remove the existing Contact header, and replace it with whatever value you like.
>
> > On Aug 2, 2022, at 1:12 AM, Ankit Jayswal <ankit.jayswal@engagely.ai> wrote:
> >
> > Hello,
> > Whenever I try the remove_hf("Contact") function the call leg is divided into the two parts and the call is not getting set up properly and not progressing.
> > I am just looking for a function that can modify the Contact header value of an existing Contact header.
> >
> > On Mon, Aug 1, 2022 at 8:31 PM Henning Westerholt <hw@gilawa.com> wrote:
> > Hello,
> >
> > 
> >
> > you need to do a “remove_hf(“Contact”)” before.
> >
> > 
> >
> > Cheers,
> >
> > 
> >
> > Henning
> >
> > 
> >
> > --
> >
> > Henning Westerholt – https://skalatan.de/blog/
> >
> > Kamailio services – https://gilawa.com
> >
> > 
> >
> > From: Ankit Jayswal <ankit.jayswal@engagely.ai>
> > Sent: Monday, August 1, 2022 4:26 PM
> > To: Henning Westerholt <hw@gilawa.com>
> > Cc: Kamailio (SER) - Users Mailing List <sr-users@lists.kamailio.org>; Amey Naik <amey.naik@engagely.ai>; Devanand Jalla <devanand.jalla@engagely.ai>
> > Subject: Re: [SR-Users] Contact header modification - Kamailio
> >
> > 
> >
> > Hello,
> > Thanks for your reply, but I am looking to replace the value in the Contact header. Which function can help me to do this ?
> > I tried,
> > assign_hf_value("Contact", "<sip:00912269240xxx@10.52.26.98:5060>");
> >
> >
> > But that is not working properly, it assigns value but previous value also remains in it.
> >
> > 
> >
> > On Mon, Aug 1, 2022 at 6:11 PM Henning Westerholt <hw@gilawa.com> wrote:
> >
> > Hello,
> >
> > 
> >
> > the topos module can do that, among other things. Alternatively there is also the topoh module, which do not need any backend storage.
> >
> > 
> >
> > Cheers,
> >
> > 
> >
> > Henning
> >
> > 
> >
> > --
> >
> > Henning Westerholt – https://skalatan.de/blog/
> >
> > Kamailio services – https://gilawa.com
> >
> > 
> >
> > From: sr-users <sr-users-bounces@lists.kamailio.org> On Behalf Of Ankit Jayswal
> > Sent: Monday, August 1, 2022 2:37 PM
> > To: sr-users@lists.kamailio.org
> > Cc: Amey Naik <amey.naik@engagely.ai>; Devanand Jalla <devanand.jalla@engagely.ai>
> > Subject: [SR-Users] Contact header modification - Kamailio
> >
> > 
> >
> > Hello Team,
> >
> > I am in need to modify the contact header in Kamailio before sending an INVITE request to the SIP trunk provider. Basically the IP address I need to modify in the contact header. Please suggest a better way to do this. Below is an example.
> >
> > OLD (Existing):
> >
> > Contact: <sip:009169240xxx@45.118.162.x:5080;alias=10.52.26.102~5080~1>
> >
> > 
> >
> > NEW (Needed):
> >
> > Contact: <sip:00912269240xxx@10.52.26.98:5060>
> >
> > I tried various functions from the textops module but no hope.
> > I am looking for a function that can replace the contact header's value. Please help me with this.
> >
> > 
> >
> > --
> >
> > Thanks & Regards,
> > Ankit Jayswal | Specialist - Software Development
> >
> > __________________________________________________________
> > Kamailio - Users Mailing List - Non Commercial Discussions
> >  * sr-users@lists.kamailio.org
> > Important: keep the mailing list in the recipients, do not reply only to the sender!
> > Edit mailing list options or unsubscribe:
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>
> --
> Alex Balashov | Principal | Evariste Systems LLC
>
> Tel: +1-706-510-6800 / +1-800-250-5920 (toll-free)
> Web: http://www.evaristesys.com/, http://www.csrpswitch.com/
>
>
> __________________________________________________________
> Kamailio - Users Mailing List - Non Commercial Discussions
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> Important: keep the mailing list in the recipients, do not reply only to the sender!
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--
Alex Balashov | Principal | Evariste Systems LLC

Tel: +1-706-510-6800 / +1-800-250-5920 (toll-free)
Web: http://www.evaristesys.com/, http://www.csrpswitch.com/


__________________________________________________________
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Important: keep the mailing list in the recipients, do not reply only to the sender!
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  * https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
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Important: keep the mailing list in the recipients, do not reply only to the sender!
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