Hi, An INVITE with following FROM and TO headers received by Kamailio: From: <sip:+11111111111@10.10.10.10;user=phone>;tag=gK006cb08b To: <sip:+12222222222@20.20.20.20;user=phone> Kamailio forward it to next node with following FROM and TO headers: From: <sip:+11111111111@10.10.10.10>;tag=gK006cb08b To: <sip:+12222222222@20.20.20.20;user=phone> After 15 min, reINVITE for the same call received by Kamailio with following FROM and TO headers: From: <sip:7272697443@71.44.13.84;user=phone>;tag=gK04c77151 To: <sip:2057030997@72.31.12.161>;tag=gK006cb08b Kamailio forward reINVITE to next node with following unusual characters in TO headers From: <sip:7272697443@71.44.13.84;user=phone>;tag=gK04c77151 To: <sip:2057030997@72.31.12.161\000\000;user=phone>;tag=gK006cb08b I was wondering if there is a bug in Kamailio to insert these unusual characters. Thanks, AS