Hi everyone,
Do we have a ready-to-use Kamailio role or configuration for:
*“Kamailio as a Stateless Smart SIP Proxy”*,
Specifically one that uses *Contact Header Encoding*?
That is — a proxy where Kamailio does not store registration state,
but encodes the client’s IP and port into the Contact header during REGISTER ,
and later decodes it from the INVITE to forward the call back to the client.
Thanks in advance!
Hi,
The set_contact_alias() / handle_ruri_alias() functions from the `nathelper` module[1] are quite ready-made for this use-case, though you may need a more sophisticated approach if the upstream registrar does not support Path[2][3].
-- Alex
[1] https://kamailio.org/docs/modules/6.0.x/modules/nathelper.html
[2] https://datatracker.ietf.org/doc/html/rfc3327
[3] https://kamailio.org/docs/modules/6.0.x/modules/path.html#path.f.add_path
On Jul 11, 2025, at 6:19 AM, Antonio via sr-users sr-users@lists.kamailio.org wrote:
Hi everyone, Do we have a ready-to-use Kamailio role or configuration for:
“Kamailio as a Stateless Smart SIP Proxy”, Specifically one that uses Contact Header Encoding?
That is — a proxy where Kamailio does not store registration state, but encodes the client’s IP and port into the Contact header during REGISTER, and later decodes it from the INVITE to forward the call back to the client. Thanks in advance! --
Antony satskiy.a@gmail.com __________________________________________________________ Kamailio - Users Mailing List - Non Commercial Discussions -- sr-users@lists.kamailio.org To unsubscribe send an email to sr-users-leave@lists.kamailio.org Important: keep the mailing list in the recipients, do not reply only to the sender!
-- Alex Balashov Principal Consultant Evariste Systems LLC Web: https://evaristesys.com, https://www.csrpswitch.com Tel: +1-706-510-6800
Thanks for the reply
I want to use Kamailio as a proxy, but a *smart one*. It doesn't store anything, but: • Modifies REGISTER requests → adds the client's IP/port to Contact • So when the PBX sends an INVITE back, Kamailio reads this data from the R-URI and forwards the call to the client
Hope it makes sense.
On Fri, Jul 11, 2025 at 10:14 PM Alex Balashov via sr-users < sr-users@lists.kamailio.org> wrote:
Hi,
The set_contact_alias() / handle_ruri_alias() functions from the `nathelper` module[1] are quite ready-made for this use-case, though you may need a more sophisticated approach if the upstream registrar does not support Path[2][3].
-- Alex
[1] https://kamailio.org/docs/modules/6.0.x/modules/nathelper.html
[2] https://datatracker.ietf.org/doc/html/rfc3327
[3] https://kamailio.org/docs/modules/6.0.x/modules/path.html#path.f.add_path
On Jul 11, 2025, at 6:19 AM, Antonio via sr-users <
sr-users@lists.kamailio.org> wrote:
Hi everyone, Do we have a ready-to-use Kamailio role or configuration for:
“Kamailio as a Stateless Smart SIP Proxy”, Specifically one that uses Contact Header Encoding?
That is — a proxy where Kamailio does not store registration state, but encodes the client’s IP and port into the Contact header during
REGISTER,
and later decodes it from the INVITE to forward the call back to the
client.
Thanks in advance!
Antony satskiy.a@gmail.com __________________________________________________________ Kamailio - Users Mailing List - Non Commercial Discussions --
sr-users@lists.kamailio.org
To unsubscribe send an email to sr-users-leave@lists.kamailio.org Important: keep the mailing list in the recipients, do not reply only to
the sender!
-- Alex Balashov Principal Consultant Evariste Systems LLC Web: https://evaristesys.com, https://www.csrpswitch.com Tel: +1-706-510-6800
Kamailio - Users Mailing List - Non Commercial Discussions -- sr-users@lists.kamailio.org To unsubscribe send an email to sr-users-leave@lists.kamailio.org Important: keep the mailing list in the recipients, do not reply only to the sender!
Hi,
Yes, that's exactly what those functions enable.
When you receive the REGISTER request, you use set_contact_alias() / add_contact_alias() to add an `;alias` parameter to the Contact, which reflects the client's external IP/port/transport. You then pass that REGISTER request onto the registrar.
When you get an incoming request from the registrar to the client, you use handle_ruri_alias() to read the `;alias` parameter and load the IP/port/transport values into the destination set ($du), while stripping the `;alias` parameter off the RURI. You then t_relay() the request, which will follow $du to the next hop read from the `;alias` parameter.
-- Alex
On Jul 11, 2025, at 4:28 PM, Antonio satskiy.a@gmail.com wrote:
Thanks for the reply
I want to use Kamailio as a proxy, but a smart one. It doesn't store anything, but: • Modifies REGISTER requests → adds the client's IP/port to Contact • So when the PBX sends an INVITE back, Kamailio reads this data from the R-URI and forwards the call to the client
Hope it makes sense.
On Fri, Jul 11, 2025 at 10:14 PM Alex Balashov via sr-users sr-users@lists.kamailio.org wrote: Hi,
The set_contact_alias() / handle_ruri_alias() functions from the `nathelper` module[1] are quite ready-made for this use-case, though you may need a more sophisticated approach if the upstream registrar does not support Path[2][3].
-- Alex
[1] https://kamailio.org/docs/modules/6.0.x/modules/nathelper.html
[2] https://datatracker.ietf.org/doc/html/rfc3327
[3] https://kamailio.org/docs/modules/6.0.x/modules/path.html#path.f.add_path
On Jul 11, 2025, at 6:19 AM, Antonio via sr-users sr-users@lists.kamailio.org wrote:
Hi everyone, Do we have a ready-to-use Kamailio role or configuration for:
“Kamailio as a Stateless Smart SIP Proxy”, Specifically one that uses Contact Header Encoding?
That is — a proxy where Kamailio does not store registration state, but encodes the client’s IP and port into the Contact header during REGISTER, and later decodes it from the INVITE to forward the call back to the client. Thanks in advance! --
Antony satskiy.a@gmail.com __________________________________________________________ Kamailio - Users Mailing List - Non Commercial Discussions -- sr-users@lists.kamailio.org To unsubscribe send an email to sr-users-leave@lists.kamailio.org Important: keep the mailing list in the recipients, do not reply only to the sender!
-- Alex Balashov Principal Consultant Evariste Systems LLC Web: https://evaristesys.com, https://www.csrpswitch.com Tel: +1-706-510-6800
Kamailio - Users Mailing List - Non Commercial Discussions -- sr-users@lists.kamailio.org To unsubscribe send an email to sr-users-leave@lists.kamailio.org Important: keep the mailing list in the recipients, do not reply only to the sender!
--
Antony satskiy.a@gmail.com
-- Alex Balashov Principal Consultant Evariste Systems LLC Web: https://evaristesys.com, https://www.csrpswitch.com Tel: +1-706-510-6800
BUT When Kamailio forwards REGISTER to Upstream(Asterisk), it will contain the REAL IP of the UAC
so later if someone will dial UAC it will not path through Kamailio
On Sat, Jul 12, 2025 at 9:32 PM Alex Balashov via sr-users < sr-users@lists.kamailio.org> wrote:
Hi,
Yes, that's exactly what those functions enable.
When you receive the REGISTER request, you use set_contact_alias() / add_contact_alias() to add an `;alias` parameter to the Contact, which reflects the client's external IP/port/transport. You then pass that REGISTER request onto the registrar.
When you get an incoming request from the registrar to the client, you use handle_ruri_alias() to read the `;alias` parameter and load the IP/port/transport values into the destination set ($du), while stripping the `;alias` parameter off the RURI. You then t_relay() the request, which will follow $du to the next hop read from the `;alias` parameter.
-- Alex
On Jul 11, 2025, at 4:28 PM, Antonio satskiy.a@gmail.com wrote:
Thanks for the reply
I want to use Kamailio as a proxy, but a smart one. It doesn't store anything, but: • Modifies REGISTER requests → adds the client's IP/port to Contact • So when the PBX sends an INVITE back, Kamailio reads this data from
the R-URI and forwards the call to the client
Hope it makes sense.
On Fri, Jul 11, 2025 at 10:14 PM Alex Balashov via sr-users <
sr-users@lists.kamailio.org> wrote:
Hi,
The set_contact_alias() / handle_ruri_alias() functions from the
`nathelper` module[1] are quite ready-made for this use-case, though you may need a more sophisticated approach if the upstream registrar does not support Path[2][3].
-- Alex
[1] https://kamailio.org/docs/modules/6.0.x/modules/nathelper.html
[2] https://datatracker.ietf.org/doc/html/rfc3327
[3]
https://kamailio.org/docs/modules/6.0.x/modules/path.html#path.f.add_path
On Jul 11, 2025, at 6:19 AM, Antonio via sr-users <
sr-users@lists.kamailio.org> wrote:
Hi everyone, Do we have a ready-to-use Kamailio role or configuration for:
“Kamailio as a Stateless Smart SIP Proxy”, Specifically one that uses Contact Header Encoding?
That is — a proxy where Kamailio does not store registration state, but encodes the client’s IP and port into the Contact header during
REGISTER,
and later decodes it from the INVITE to forward the call back to the
client.
Thanks in advance!
Antony satskiy.a@gmail.com __________________________________________________________ Kamailio - Users Mailing List - Non Commercial Discussions --
sr-users@lists.kamailio.org
To unsubscribe send an email to sr-users-leave@lists.kamailio.org Important: keep the mailing list in the recipients, do not reply only
to the sender!
-- Alex Balashov Principal Consultant Evariste Systems LLC Web: https://evaristesys.com, https://www.csrpswitch.com Tel: +1-706-510-6800
Kamailio - Users Mailing List - Non Commercial Discussions --
sr-users@lists.kamailio.org
To unsubscribe send an email to sr-users-leave@lists.kamailio.org Important: keep the mailing list in the recipients, do not reply only to
the sender!
--
Antony satskiy.a@gmail.com
-- Alex Balashov Principal Consultant Evariste Systems LLC Web: https://evaristesys.com, https://www.csrpswitch.com Tel: +1-706-510-6800
Kamailio - Users Mailing List - Non Commercial Discussions -- sr-users@lists.kamailio.org To unsubscribe send an email to sr-users-leave@lists.kamailio.org Important: keep the mailing list in the recipients, do not reply only to the sender!
Use Path for that purpose ( rfc3327)
On Mon, Jul 14, 2025, 14:36 Antonio via sr-users < sr-users@lists.kamailio.org> wrote:
BUT When Kamailio forwards REGISTER to Upstream(Asterisk), it will contain the REAL IP of the UAC
so later if someone will dial UAC it will not path through Kamailio
On Sat, Jul 12, 2025 at 9:32 PM Alex Balashov via sr-users < sr-users@lists.kamailio.org> wrote:
Hi,
Yes, that's exactly what those functions enable.
When you receive the REGISTER request, you use set_contact_alias() / add_contact_alias() to add an `;alias` parameter to the Contact, which reflects the client's external IP/port/transport. You then pass that REGISTER request onto the registrar.
When you get an incoming request from the registrar to the client, you use handle_ruri_alias() to read the `;alias` parameter and load the IP/port/transport values into the destination set ($du), while stripping the `;alias` parameter off the RURI. You then t_relay() the request, which will follow $du to the next hop read from the `;alias` parameter.
-- Alex
On Jul 11, 2025, at 4:28 PM, Antonio satskiy.a@gmail.com wrote:
Thanks for the reply
I want to use Kamailio as a proxy, but a smart one. It doesn't store anything, but: • Modifies REGISTER requests → adds the client's IP/port to Contact • So when the PBX sends an INVITE back, Kamailio reads this data from
the R-URI and forwards the call to the client
Hope it makes sense.
On Fri, Jul 11, 2025 at 10:14 PM Alex Balashov via sr-users <
sr-users@lists.kamailio.org> wrote:
Hi,
The set_contact_alias() / handle_ruri_alias() functions from the
`nathelper` module[1] are quite ready-made for this use-case, though you may need a more sophisticated approach if the upstream registrar does not support Path[2][3].
-- Alex
[1] https://kamailio.org/docs/modules/6.0.x/modules/nathelper.html
[2] https://datatracker.ietf.org/doc/html/rfc3327
[3]
https://kamailio.org/docs/modules/6.0.x/modules/path.html#path.f.add_path
On Jul 11, 2025, at 6:19 AM, Antonio via sr-users <
sr-users@lists.kamailio.org> wrote:
Hi everyone, Do we have a ready-to-use Kamailio role or configuration for:
“Kamailio as a Stateless Smart SIP Proxy”, Specifically one that uses Contact Header Encoding?
That is — a proxy where Kamailio does not store registration state, but encodes the client’s IP and port into the Contact header during
REGISTER,
and later decodes it from the INVITE to forward the call back to the
client.
Thanks in advance!
Antony satskiy.a@gmail.com __________________________________________________________ Kamailio - Users Mailing List - Non Commercial Discussions --
sr-users@lists.kamailio.org
To unsubscribe send an email to sr-users-leave@lists.kamailio.org Important: keep the mailing list in the recipients, do not reply only
to the sender!
-- Alex Balashov Principal Consultant Evariste Systems LLC Web: https://evaristesys.com, https://www.csrpswitch.com Tel: +1-706-510-6800
Kamailio - Users Mailing List - Non Commercial Discussions --
sr-users@lists.kamailio.org
To unsubscribe send an email to sr-users-leave@lists.kamailio.org Important: keep the mailing list in the recipients, do not reply only
to the sender!
--
Antony satskiy.a@gmail.com
-- Alex Balashov Principal Consultant Evariste Systems LLC Web: https://evaristesys.com, https://www.csrpswitch.com Tel: +1-706-510-6800
Kamailio - Users Mailing List - Non Commercial Discussions -- sr-users@lists.kamailio.org To unsubscribe send an email to sr-users-leave@lists.kamailio.org Important: keep the mailing list in the recipients, do not reply only to the sender!
--
*Antony* satskiy.a@gmail.com
Kamailio - Users Mailing List - Non Commercial Discussions -- sr-users@lists.kamailio.org To unsubscribe send an email to sr-users-leave@lists.kamailio.org Important: keep the mailing list in the recipients, do not reply only to the sender!
https://www.kamailio.org/docs/modules/5.0.x/modules/nathelper.html#nathelper... ? With combination of alias and other parameter, means you can store full original contact header (encoded) in a Contact params as well. Yes, it brakes RFC, but you can handle it manually
Le lun. 14 juil. 2025 à 14:36, Antonio via sr-users < sr-users@lists.kamailio.org> a écrit :
BUT When Kamailio forwards REGISTER to Upstream(Asterisk), it will contain the REAL IP of the UAC
so later if someone will dial UAC it will not path through Kamailio
On Sat, Jul 12, 2025 at 9:32 PM Alex Balashov via sr-users < sr-users@lists.kamailio.org> wrote:
Hi,
Yes, that's exactly what those functions enable.
When you receive the REGISTER request, you use set_contact_alias() / add_contact_alias() to add an `;alias` parameter to the Contact, which reflects the client's external IP/port/transport. You then pass that REGISTER request onto the registrar.
When you get an incoming request from the registrar to the client, you use handle_ruri_alias() to read the `;alias` parameter and load the IP/port/transport values into the destination set ($du), while stripping the `;alias` parameter off the RURI. You then t_relay() the request, which will follow $du to the next hop read from the `;alias` parameter.
-- Alex
On Jul 11, 2025, at 4:28 PM, Antonio satskiy.a@gmail.com wrote:
Thanks for the reply
I want to use Kamailio as a proxy, but a smart one. It doesn't store anything, but: • Modifies REGISTER requests → adds the client's IP/port to Contact • So when the PBX sends an INVITE back, Kamailio reads this data from
the R-URI and forwards the call to the client
Hope it makes sense.
On Fri, Jul 11, 2025 at 10:14 PM Alex Balashov via sr-users <
sr-users@lists.kamailio.org> wrote:
Hi,
The set_contact_alias() / handle_ruri_alias() functions from the
`nathelper` module[1] are quite ready-made for this use-case, though you may need a more sophisticated approach if the upstream registrar does not support Path[2][3].
-- Alex
[1] https://kamailio.org/docs/modules/6.0.x/modules/nathelper.html
[2] https://datatracker.ietf.org/doc/html/rfc3327
[3]
https://kamailio.org/docs/modules/6.0.x/modules/path.html#path.f.add_path
On Jul 11, 2025, at 6:19 AM, Antonio via sr-users <
sr-users@lists.kamailio.org> wrote:
Hi everyone, Do we have a ready-to-use Kamailio role or configuration for:
“Kamailio as a Stateless Smart SIP Proxy”, Specifically one that uses Contact Header Encoding?
That is — a proxy where Kamailio does not store registration state, but encodes the client’s IP and port into the Contact header during
REGISTER,
and later decodes it from the INVITE to forward the call back to the
client.
Thanks in advance!
Antony satskiy.a@gmail.com __________________________________________________________ Kamailio - Users Mailing List - Non Commercial Discussions --
sr-users@lists.kamailio.org
To unsubscribe send an email to sr-users-leave@lists.kamailio.org Important: keep the mailing list in the recipients, do not reply only
to the sender!
-- Alex Balashov Principal Consultant Evariste Systems LLC Web: https://evaristesys.com, https://www.csrpswitch.com Tel: +1-706-510-6800
Kamailio - Users Mailing List - Non Commercial Discussions --
sr-users@lists.kamailio.org
To unsubscribe send an email to sr-users-leave@lists.kamailio.org Important: keep the mailing list in the recipients, do not reply only
to the sender!
--
Antony satskiy.a@gmail.com
-- Alex Balashov Principal Consultant Evariste Systems LLC Web: https://evaristesys.com, https://www.csrpswitch.com Tel: +1-706-510-6800
Kamailio - Users Mailing List - Non Commercial Discussions -- sr-users@lists.kamailio.org To unsubscribe send an email to sr-users-leave@lists.kamailio.org Important: keep the mailing list in the recipients, do not reply only to the sender!
--
*Antony* satskiy.a@gmail.com
Kamailio - Users Mailing List - Non Commercial Discussions -- sr-users@lists.kamailio.org To unsubscribe send an email to sr-users-leave@lists.kamailio.org Important: keep the mailing list in the recipients, do not reply only to the sender!
route[REGISTER] { if (!is_method("REGISTER")) return; if (nat_uac_test("19")) { xlog("L_INFO", "NAT detected for REGISTER request\n"); fix_nated_contact(); msg_apply_changes(); } encode_contact("proxy_ip", ADV_HOST); t_relay(); exit; }
I have found this but ima little bit confused that i have to use msg_apply_changes(); before doing encode_contact() because otherwise kama respond that buffer is overloded
On Fri, Jul 18, 2025 at 9:31 AM Ihor Olkhovskyi via sr-users < sr-users@lists.kamailio.org> wrote:
https://www.kamailio.org/docs/modules/5.0.x/modules/nathelper.html#nathelper... ? With combination of alias and other parameter, means you can store full original contact header (encoded) in a Contact params as well. Yes, it brakes RFC, but you can handle it manually
Le lun. 14 juil. 2025 à 14:36, Antonio via sr-users < sr-users@lists.kamailio.org> a écrit :
BUT When Kamailio forwards REGISTER to Upstream(Asterisk), it will contain the REAL IP of the UAC
so later if someone will dial UAC it will not path through Kamailio
On Sat, Jul 12, 2025 at 9:32 PM Alex Balashov via sr-users < sr-users@lists.kamailio.org> wrote:
Hi,
Yes, that's exactly what those functions enable.
When you receive the REGISTER request, you use set_contact_alias() / add_contact_alias() to add an `;alias` parameter to the Contact, which reflects the client's external IP/port/transport. You then pass that REGISTER request onto the registrar.
When you get an incoming request from the registrar to the client, you use handle_ruri_alias() to read the `;alias` parameter and load the IP/port/transport values into the destination set ($du), while stripping the `;alias` parameter off the RURI. You then t_relay() the request, which will follow $du to the next hop read from the `;alias` parameter.
-- Alex
On Jul 11, 2025, at 4:28 PM, Antonio satskiy.a@gmail.com wrote:
Thanks for the reply
I want to use Kamailio as a proxy, but a smart one. It doesn't store anything, but: • Modifies REGISTER requests → adds the client's IP/port to Contact • So when the PBX sends an INVITE back, Kamailio reads this data from
the R-URI and forwards the call to the client
Hope it makes sense.
On Fri, Jul 11, 2025 at 10:14 PM Alex Balashov via sr-users <
sr-users@lists.kamailio.org> wrote:
Hi,
The set_contact_alias() / handle_ruri_alias() functions from the
`nathelper` module[1] are quite ready-made for this use-case, though you may need a more sophisticated approach if the upstream registrar does not support Path[2][3].
-- Alex
[1] https://kamailio.org/docs/modules/6.0.x/modules/nathelper.html
[2] https://datatracker.ietf.org/doc/html/rfc3327
[3]
https://kamailio.org/docs/modules/6.0.x/modules/path.html#path.f.add_path
On Jul 11, 2025, at 6:19 AM, Antonio via sr-users <
sr-users@lists.kamailio.org> wrote:
Hi everyone, Do we have a ready-to-use Kamailio role or configuration for:
“Kamailio as a Stateless Smart SIP Proxy”, Specifically one that uses Contact Header Encoding?
That is — a proxy where Kamailio does not store registration state, but encodes the client’s IP and port into the Contact header during
REGISTER,
and later decodes it from the INVITE to forward the call back to the
client.
Thanks in advance!
Antony satskiy.a@gmail.com __________________________________________________________ Kamailio - Users Mailing List - Non Commercial Discussions --
sr-users@lists.kamailio.org
To unsubscribe send an email to sr-users-leave@lists.kamailio.org Important: keep the mailing list in the recipients, do not reply
only to the sender!
-- Alex Balashov Principal Consultant Evariste Systems LLC Web: https://evaristesys.com, https://www.csrpswitch.com Tel: +1-706-510-6800
Kamailio - Users Mailing List - Non Commercial Discussions --
sr-users@lists.kamailio.org
To unsubscribe send an email to sr-users-leave@lists.kamailio.org Important: keep the mailing list in the recipients, do not reply only
to the sender!
--
Antony satskiy.a@gmail.com
-- Alex Balashov Principal Consultant Evariste Systems LLC Web: https://evaristesys.com, https://www.csrpswitch.com Tel: +1-706-510-6800
Kamailio - Users Mailing List - Non Commercial Discussions -- sr-users@lists.kamailio.org To unsubscribe send an email to sr-users-leave@lists.kamailio.org Important: keep the mailing list in the recipients, do not reply only to the sender!
--
*Antony* satskiy.a@gmail.com
Kamailio - Users Mailing List - Non Commercial Discussions -- sr-users@lists.kamailio.org To unsubscribe send an email to sr-users-leave@lists.kamailio.org Important: keep the mailing list in the recipients, do not reply only to the sender!
-- Best regards, Ihor (Igor) __________________________________________________________ Kamailio - Users Mailing List - Non Commercial Discussions -- sr-users@lists.kamailio.org To unsubscribe send an email to sr-users-leave@lists.kamailio.org Important: keep the mailing list in the recipients, do not reply only to the sender!
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Alex Balashov -
Antonio -
Ihor Olkhovskyi -
Yuriy G