The RFCs are correct; strictly speaking, a proxy should not alter the encapsulated message body, or most other SIP message attributes.

Kamailio is a huge toolbox with many capabilities, not unlike a programming language. It gives one the power to do a great many things.

Some of these things aren't standards-compliant, and that's okay. The ends justify the means. Other times--many times--call for judicious restraint, as just because Kamailio can do something doesn't mean that you should do it, or that using a tool Kamailio offers to do something bluntly is a good substitute for doing something delicately.

Knowing the difference is the soul of experience. :-)

-- Alex

On 6 Mar 2024, at 06:19, Valentin Christoph via sr-users sr-users@lists.kamailio.org wrote:

Hi all, it might be a minor issue, or it might not be an issue at all, but I stumbled over following statements in RFC 3261: Chapter 16.6 Request Forwarding (of a proxy) 1. Copy request

     The proxy starts with a copy of the received request.  The copy
     MUST initially contain all of the header fields from the
     received request.  Fields not detailed in the processing
     described below MUST NOT be removed.  The copy SHOULD maintain
     the ordering of the header fields as in the received request.
     The proxy MUST NOT reorder field values with a common field
     name (See Section 7.3.1).  The proxy MUST NOT add to, modify,
     or remove the message body.

     An actual implementation need not perform a copy; the primary
     requirement is that the processing for each next hop begin with
     the same request.

Chapter 16.7 Response Processing (at a proxy) 9. Forward response

     After performing the processing described in steps "Aggregate
     Authorization Header Field Values" through "Record-Route", the
     proxy MAY perform any feature specific manipulations on the
     selected response.  The proxy MUST NOT add to, modify, or
     remove the message body.  Unless otherwise specified, the proxy
     MUST NOT remove any header field values other than the Via
     header field value discussed in Section 16.7 Item 3.  In
     particular, the proxy MUST NOT remove any "received" parameter

On the other hand, everywhere in the Internet (starting with stackoverflow), you can read it is OK, if a SIP proxy modifies a body, and also kamailio allows it. Might be a question for the coffee break. All the best Christoph __________________________________________________________ Kamailio - Users Mailing List - Non Commercial Discussions 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! Edit mailing list options or unsubscribe: