[SIPForum-discussion] What to do if sent-by value is missing in responses while proxy processing them ?

Yevgen Krapiva ykrapiva at gmail.com
Tue Apr 21 09:09:07 UTC 2009

> Section 18.1.1 Sending requests
> ....
> Before a request is sent, the client transport MUST insert a value of
> the "sent-by" field into the Via header field.  This field contains
> an IP address or host name, and port.  The usage of an FQDN is

Here is a SIP call flow examples http://www.ietf.org/rfc/rfc3665.txt

Can anybody show me any sent-by parameters there ? :)
Noone uses sent-by values. Checked with Xlite, Ekiga softphones.

But in anyway, I try to make correct proxy, but this issue makes me stuck.

Can anybody comment this ?

2009/4/18, Tomasz Zieleniewski <tzieleniewski at gmail.com>:
> Hi,
> If the sent-by value is not present then it means that it doesn't match
> proxy
> address. In such case as it it written message is discarded by proxy.
> Regards
> - Tomasz Zieleniewski
> 2009/4/17 Yevgen Krapiva <ykrapiva at gmail.com>:
>> Hi all.
>> This is quotation from RFC3261 about stateless response processing:
>>>  Response processing as described in Section 16.7 does not apply to a
>>>  proxy behaving statelessly.  When a response arrives at a stateless
>>>  proxy, the proxy MUST inspect the sent-by value in the first
>>>  (topmost) Via header field value.
>>>  ...
>>> If the address does not match the
>>> proxy, the message MUST be silently discarded.
>> What to do if sent-by value is not present in responses ? :)
>> For example, I didn't find any in rfc3665 (sip call flow examples).
>> _______________________________________________
>> This is the SIP Forum discussion mailing list
>> TO UNSUBSCRIBE, or edit your delivery options, please visit
>> http://sipforum.org/mailman/listinfo/discussion
>> Post to the list at discussion at sipforum.org

More information about the discussion mailing list