[Asterisk-Users] "Proxy Authentication Required" issue

[Kevin P. Fleming]

Tim Chase wrote:

> Is it REQUIRED for Asterisk that thesecond Invite which is a response to the 407 that has the proper authentication information to use the same call ID and Cseq or this should not matter?

This is not an Asterisk requirement, it's a SIP RFC compliance
requirement. The random value (nonce) that is sent as part of the
initial 407 response is specific to that Call-ID, as the RFC mandates.
If Asterisk receives an INVITE for a different Call-ID, it will generate
a new nonce, thus ignoring the authentication info including in the INVITE.

In other words: your SBC is broken.