From: "Murat Artun" <[EMAIL PROTECTED]> What would be the possible call scenarios for two SIP UAs both behind NAT?
Should a SIP proxy always be used? In case when A SIP proxy is not used, is it possible to make a direct call from one to other by using some workaorunds such as port forwarding on the NAT? Generally, if each UA works behind the NAT for outside calls, the two UAs should be able to communicate with each other. (A UA that works behind a NAT masquerades itself to appear to not be behind a NAT, so each UA treats the other UA as not being behind a NAT.) The complication is that the NAT "must be able to hairpin connections", that is, if the NAT emits a packet out its WAN interface addressed to the WAN interface, it needs to be able to receive the packet. Any IP device should handle hairpinning correctly, but some NATs do not. Dale _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
