I have searched the archive for an answer to this question, and I did not find it. If I missed, I apologize. Please point me in the right direction. I am having a problem with the pa module of ser (0.8.12). Using ethereal, I see that in response to a SUBSCRIBE, ser will sometimes send an OK and then a NOTIFY. However, other times ser sends the NOTIFY and then the OK. For a single UA sending multiple SUBSCRIBE's to ser, about half of the OK's are sent first and about half of the NOTIFY's are sent first. This is a problem because I am running the UA behind a SIP-aware firewall which expects the OK first. If the OK is not received, the NOTIFY will not be allowed back through the firewall. Looking at RFC 3265, 3.1.4.1: "This SUBSCRIBE request will be confirmed with a final response. 200-class responses indicate that the subscription has been accepted, and that a NOTIFY will be sent immediately." Looking at RFC 3265, 3.1.6.2: "Upon successfully accepting or refreshing a subscription, notifiers MUST send a NOTIFY message immediately to communicate the current resource state to the subscriber. This NOTIFY message is sent on the same dialog as created by the SUBSCRIBE response. <snip> Note that a NOTIFY message is always sent immediately after any 200-class response to a SUBSCRIBE request, regardless of whether the subscription has already been authorized." My interpretation is that the RFC requires the OK to be sent first. Is that a valid interpretation? Is there an easy fix for this (perhaps in ser.cfg) or will this require a code change?