Hi All,
I have a question regarding the functioning of the Iptel proxy server. As far as I know, only when there is "rports" field present in the "via" header field in a SIP request(INVITE for ex.), the proxy server should send the responses to the source port from which the request is sent. I would like to know if there is any other case in which the responses are sent to the source port instead of the VIA port.
Please provide me with the details on this.
thanks Mahesh
On Sep 29, 2004 at 11:49, mahesh mahesha@intoto.com wrote:
Hi All,
I have a question regarding the functioning of the Iptel proxy server. As far as I know, only when there is "rports" field present in the "via" header field in a SIP request(INVITE for ex.), the proxy server should send the responses to the source port from which the request is sent. I would like to know if there is any other case in which the responses are sent to the source port instead of the VIA port.
No, for UDP there isn't (if no rport is present and you don't use force_rport() in your config, the response is sent to the via port if present and if not, to 5060). For TCP, ser will always try to reuse the original connection, so if the connection on which it received the request is still up, it will send the reply back on it.
Andrei
Hi Andrei, Thanks for the reply.
I am using the publicly available iptel proxy server(195.37.77.99) to test my implementation of SIP-ALG. I am using the following configuration
HOST1(winXP)---FW---Internet---HOST2(winCP)
FW is the firewall/NAT device, which has the ALG implementation. I am using SJPhone on my hosts to communicate using SIP(UDP). I observe that the responses to requests sent by HOST1 come from the proxy(iptel) to the source port(of FW), from which the request was sent, instead of on VIA. There is no "rport" field in the VIA header field of the request.
Does anyone know if the iptel proxy server is configured to use "force_rport".
thanks Mahesh
On Sep 29, 2004 at 11:49, mahesh mahesha@intoto.com wrote:
Hi All,
I have a question regarding the functioning of the Iptel proxy server. As far as I know, only when there is "rports" field present in the "via" header field in a SIP request(INVITE for ex.), the proxy server should
send
the responses to the source port from which the request is sent. I would like to know if there is any other case in which the responses are sent to the source port instead of the VIA port.
No, for UDP there isn't (if no rport is present and you don't use force_rport() in your config, the response is sent to the via port if present and if not, to 5060). For TCP, ser will always try to reuse the original connection, so if the connection on which it received the request is still up, it will send the reply back on it.
Andrei
On Oct 01, 2004 at 10:16, mahesh mahesha@intoto.com wrote:
Hi Andrei, Thanks for the reply.
I am using the publicly available iptel proxy server(195.37.77.99) to test my implementation of SIP-ALG. I am using the following configuration
HOST1(winXP)---FW---Internet---HOST2(winCP)
FW is the firewall/NAT device, which has the ALG implementation. I am using SJPhone on my hosts to communicate using SIP(UDP). I observe that the responses to requests sent by HOST1 come from the proxy(iptel) to the source port(of FW), from which the request was sent, instead of on VIA. There is no "rport" field in the VIA header field of the request.
Does anyone know if the iptel proxy server is configured to use "force_rport".
Yes, it is.
Andrei
Andrei,
Any significant reason on why this is being done??
Mahesh
At 08:59 PM 10/1/2004, Andrei Pelinescu-Onciul wrote:
On Oct 01, 2004 at 10:16, mahesh mahesha@intoto.com wrote:
Hi Andrei, Thanks for the reply.
I am using the publicly available iptel proxy server(195.37.77.99) to test my implementation of SIP-ALG. I am using the following configuration
HOST1(winXP)---FW---Internet---HOST2(winCP)
FW is the firewall/NAT device, which has the ALG implementation. I am
using
SJPhone on my hosts to communicate using SIP(UDP). I observe that the responses to requests sent by HOST1 come from the proxy(iptel) to the source port(of FW), from which the request was sent, instead of on VIA. There is no "rport" field in the VIA header field of the request.
Does anyone know if the iptel proxy server is configured to use "force_rport".
Yes, it is.
Andrei
Hi Mahesh,
force_rport() is used as a part of the NAT traversal solution. When a request come across a NAT, the server will see a different port (the one of the NAT), instead of the one advertise in VIA. And to be able to pass the reply back to UAC (through NAT), the server MUST use the detected NAT port (otherwise the NAT will not allow the message to pass).
best regards, Marian
mahesh wrote:
Andrei,
Any significant reason on why this is being done??
Mahesh
At 08:59 PM 10/1/2004, Andrei Pelinescu-Onciul wrote:
On Oct 01, 2004 at 10:16, mahesh mahesha@intoto.com wrote:
Hi Andrei, Thanks for the reply.
I am using the publicly available iptel proxy server(195.37.77.99)
to test
my implementation of SIP-ALG. I am using the following configuration
HOST1(winXP)---FW---Internet---HOST2(winCP)
FW is the firewall/NAT device, which has the ALG implementation. I
am using
SJPhone on my hosts to communicate using SIP(UDP). I observe that the responses to requests sent by HOST1 come from the proxy(iptel) to the source port(of FW), from which the request was sent, instead of on
VIA.
There is no "rport" field in the VIA header field of the request.
Does anyone know if the iptel proxy server is configured to use "force_rport".
Yes, it is.
Andrei
Serusers mailing list serusers@lists.iptel.org http://lists.iptel.org/mailman/listinfo/serusers
On Oct 05, 2004 at 14:48, mahesh mahesha@intoto.com wrote:
Andrei,
Any significant reason on why this is being done??
Because there are a lot of broken UAs not including rport in their Vias and probably all UAs are symmetric these days.
Andrei
At 08:59 PM 10/1/2004, Andrei Pelinescu-Onciul wrote:
On Oct 01, 2004 at 10:16, mahesh mahesha@intoto.com wrote:
Hi Andrei, Thanks for the reply.
I am using the publicly available iptel proxy server(195.37.77.99) to
test
my implementation of SIP-ALG. I am using the following configuration
HOST1(winXP)---FW---Internet---HOST2(winCP)
FW is the firewall/NAT device, which has the ALG implementation. I am
using
SJPhone on my hosts to communicate using SIP(UDP). I observe that the responses to requests sent by HOST1 come from the proxy(iptel) to the source port(of FW), from which the request was sent, instead of on VIA. There is no "rport" field in the VIA header field of the request.
Does anyone know if the iptel proxy server is configured to use "force_rport".
Yes, it is.
Andrei
At 11:18 AM 10/5/2004, mahesh wrote:
Andrei,
Any significant reason on why this is being done??
yes. to make sure that majority of devices that are symmetric but are silly not to advertise it using rport work. It will fail for those which are not symmetric -- I am not worried about them too much, they should be.
-jiri
Mahesh
At 08:59 PM 10/1/2004, Andrei Pelinescu-Onciul wrote:
On Oct 01, 2004 at 10:16, mahesh mahesha@intoto.com wrote:
Hi Andrei, Thanks for the reply.
I am using the publicly available iptel proxy server(195.37.77.99) to test my implementation of SIP-ALG. I am using the following configuration
HOST1(winXP)---FW---Internet---HOST2(winCP)
FW is the firewall/NAT device, which has the ALG implementation. I am using SJPhone on my hosts to communicate using SIP(UDP). I observe that the responses to requests sent by HOST1 come from the proxy(iptel) to the source port(of FW), from which the request was sent, instead of on VIA. There is no "rport" field in the VIA header field of the request.
Does anyone know if the iptel proxy server is configured to use "force_rport".
Yes, it is.
Andrei
Serusers mailing list serusers@lists.iptel.org http://lists.iptel.org/mailman/listinfo/serusers
-- Jiri Kuthan http://iptel.org/~jiri/
-
Andrei Pelinescu-Onciul -
Jiri Kuthan -
mahesh -
Marian Dumitru