Today we cannot connect an Ekiga client to our Asterisk SIP server.
The error reported by Ekiga was “loop detected” (with a poor italian translation “rilevato ciclo”).
We found a solution by Asterisk CLI command “sip set debug on” and by inspecting the debugging log: Ekiga sends packets with a wrong address in class 169.254.0.0/16 assigned to eth0 (without cable) by DHCP.
As reported by RFC 169.254.0.0/16 is the “link local” block.
It was set aside for this special use in the Standards Track document, RFC 3927 and was further documented in the Best Current Practice RFC 5735. It is allocated for communication between hosts on a single link. Hosts obtain these addresses by auto-configuration, such as when a DHCP server cannot be found.
RFC specify that a router MUST NOT forward a packet with an IPv4 Link-Local source or destination address, and so Ekiga shouldn’t send a SIP packet with this kind of address.
Anyway, to resolve this problem, stop dhcp on a disconnected interface or remove this assigned address.