Hello, I am using ser+nathelper+rtpproxy on a FC3 system (2.6.9-1.667) ser version is 0.8.14. usrloc params is set to 0 (modparam("usrloc", "db_mode", 0)) There are two Windows Messenger clients the one behind NAT, the other not. "REGISTER" works well for both clients, but "SUBSCRIBE" not. Ser replies that no user can be found in the usrloc and the "SUBSCRIBE" message fails with "408 Request Timeout" Users and their contacts have already been added by means of the serctl utility. SIP/2.0 408 Request Timeout..Via: SIP/2.0/UDP 172.16.60.123:7397;rport=1839 ..From: &quot;1000(a)kentauros.rtd.algo.com.gr&quot; <sip:1000@kentauros.rtd.algo.com.g r>;tag=06f4a48b5efb4ef99362475de6f155af;epid=7ef24ed5a6..To: <sip:1001@kent auros.rtd.algo.com.gr>;tag=92fb9945638573c26d114962da30e489-3fbd..Call-ID: 23185c1c2a5a46be8b68785bbc12a22e..CSeq: 1 SUBSCRIBE..Server: Sip EXpress ro uter (0.8.14 (i386/linux))..Content-Length: 0..Warning: 392 193.92.74.49:50 60 "Noisy feedback tells: pid=3985 req_src_ip=172.16.60.123 req_src_port=1 839 in_uri=sip:1001@kentauros.rtd.algo.com.gr out_uri=sip:62.103.218.177:16 213 via_cnt==0".... ......................... 0(3984) SIP Request: 0(3984) method: <SUBSCRIBE> 0(3984) uri: <sip:1001@kentauros.rtd.algo.com.gr> 0(3984) version: <SIP/2.0> 0(3984) parse_headers: flags=1 0(3984) end of header reached, state=5 0(3984) parse_headers: Via found, flags=1 0(3984) parse_headers: this is the first via 0(3984) After parse_msg... 0(3984) preparing to run routing scripts... 0(3984) DEBUG : is_maxfwd_present: searching for max_forwards header 0(3984) parse_headers: flags=128 0(3984) DEBUG: is_maxfwd_present: value = 70 0(3984) check_via_address(172.16.60.123, 172.16.60.123, 0) 0(3984) parse_headers: flags=64 0(3984) end of header reached, state=9 0(3984) DEBUG: get_hdr_field: <To> [38]; uri=[sip:1001@kentauros.rtd.algo.com.g r] 0(3984) DEBUG: to body [<sip:1001@kentauros.rtd.algo.com.gr> ] 0(3984) get_hdr_field: cseq <CSeq>: <1> <SUBSCRIBE> 0(3984) LOG: Someone trying to register from private IP, rewriting 0(3984) parse_headers: flags=64 0(3984) DEBUG: add_param: tag=15f714ddfaa544dc91e3031e37618560 0(3984) DEBUG: add_param: epid=7ef24ed5a6 0(3984) end of header reached, state=29 0(3984) parse_headers: flags=256 0(3984) DEBUG: get_hdr_body : content_length=0 0(3984) found end of header 0(3984) find_first_route(): No Route headers found 0(3984) loose_route(): There is no Route HF 0(3984) check_self - checking if host==us: 25==12 && [kentauros.rtd.algo.com.g r] == [193.92.74.49] 0(3984) check_self - checking if port 5060 matches port 5060 0(3984) check_self - checking if host==us: 25==12 && [kentauros.rtd.algo.com.g r] == [193.92.74.49] 0(3984) check_self - checking if port 5060 matches port 5060 0(3984) lookup(): '1001' Not found in usrloc 0(3984) check_self - checking if host==us: 25==12 && [kentauros.rtd.algo.com.g r] == [193.92.74.49] 0(3984) check_self - checking if port 5060 matches port 5060 0(3984) rwrite(): Rewriting Request-URI with 'sip:62.103.218.177:16213' 0(3984) parse_headers: flags=-1 0(3984) DEBUG: t_addifnew: msg id=25 , global msg id=24 , T on entrance=0xfffff fff 0(3984) parse_headers: flags=-1 0(3984) parse_headers: flags=60 0(3984) t_lookup_request: start searching: hash=31903, isACK=0 0(3984) DEBUG: proceeding to pre-RFC3261 transaction matching 0(3984) DEBUG: non-ACK matched 0(3984) DEBUG: t_lookup_request: transaction found (T=0xf0c120) 0(3984) DBG: t_retransmit_reply: nothing to retransmit 0(3984) DEBUG:destroy_avp_list: destroing list (nil) 0(3984) receive_msg: cleaning up 1(3985) DEBUG: timer routine:7,tl=0xf0c248 next=(nil) 1(3985) DEBUG: retransmission_handler : request resending (t=0xf0c120, SUBSCRIB E ... ) 1(3985) DEBUG: add_to_tail_of_timer[7]: 0xf0c248 1(3985) DEBUG: retransmission_handler : done 1(3985) DEBUG: timer routine:7,tl=0xf0c248 next=(nil) 1(3985) DEBUG: retransmission_handler : request resending (t=0xf0c120, SUBSCRIB E ... ) 1(3985) DEBUG: add_to_tail_of_timer[7]: 0xf0c248 1(3985) DEBUG: retransmission_handler : done Please advice ... Thank you in advance Yannis