I could send udp test data from .100.11(FreeBSD4.8) to .100.26( sip proxy(SER-0.8.10), tel.no-ip.com:5064), but when BT101 sent real "REGISTER" packet to .100.26, .100.30(eth0) just sent back "destination unreachable" to .100.7. (NOTE: http://tel.no-ip.com works fine on .100.11) It looks like the same IP headers between SENDIP's udp test data and BT101's udp "REGISTER" packet except data lengths. My questions are: (1) Why not BT101 can send udp packet to .100.26? (2) Why SENDIP's trailer was changed from "2B2801...." to "000...." when it goes from (.100.11->.100.30) to (.100.30->.100.26)? ======== Internet ======== |global address(DHCP) ----------- | ADSL | | modem | | w/router| ----------- |.1 192.168.0.0/24 -------------------------------- |.30(eth1,eth1:0 tel.no-ip.com) ------------------- | RHL7.3 | | Linux-2.4.18-3 | | iptables V1.2.5 | ------------------- |.30(eth0) 192.168.100.0/24 ---------------------------------------- |.11 |.7 |.26 ------------ ------- ------------ |FreeBSD4.8| |BT101| |FreeBSD4.8 | ------------ ------- |ser-0.8.10 | sendip sip phone ------------- tel.no-ip.com:5064 [root@sp98n zenkato]# /sbin/iptables -t nat -A PREROUTING -d 218.225.79.229 -p udp --dport 5064 -j DNAT --to 192.168.100.26 [root@sp98n zenkato]# /sbin/iptables -t nat -A POSTROUTING -d 192.168.100.26 -s 192.168.100.0/24 -p udp --dport 5064 -j SNAT --to 192.168.100.30 [root@sp98n zenkato]# /usr/sbin/tcpdump -i eth0 tcpdump: listening on eth0 17:53:00.055194 192.168.100.7.5071 > fe229.ade.ttcn.ne.jp.5064: udp 532 (DF) 17:53:00.055463 fe229.ade.ttcn.ne.jp > 192.168.100.7: icmp: fe229.ade.ttcn.ne.jp udp port 5064 unreachable [tos 0xc0] ^^^^^^^^^^^ -----------SENDIP trailer changed?------------- Frame 1 (60 bytes on wire, 60 bytes captured) Arrival Time: Aug 30, 2003 22:09:44.395822000 Time delta from previous packet: 0.000000000 seconds Time relative to first packet: 0.000000000 seconds Frame Number: 1 Packet Length: 60 bytes Capture Length: 60 bytes Ethernet II, Src: 00:80:c8:8a:73:dc, Dst: 00:e0:18:80:4c:8f Destination: 00:e0:18:80:4c:8f (AsustekC_80:4c:8f) Source: 00:80:c8:8a:73:dc (D-Link_8a:73:dc) Type: IP (0x0800) Trailer: 2B28010000010000000000000374656C... ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Internet Protocol, Src Addr: 192.168.100.11 (192.168.100.11), Dst Addr: 218.225.79.229 (218.225.79.229) Version: 4 Header length: 20 bytes Differentiated Services Field: 0x00 (DSCP 0x00: Default; ECN: 0x00) 0000 00.. = Dethereal-test-udp-1 Frame 2 (60 bytes on wire, 60 bytes captured) Arrival Time: Aug 30, 2003 22:09:44.396098000 Time delta from previous packet: 0.000276000 seconds Time relative to first packet: 0.000276000 seconds Frame Number: 2 Packet Length: 60 bytes Capture Length: 60 bytes Ethernet II, Src: 00:e0:18:80:4c:8f, Dst: 00:00:e8:77:50:06 Destination: 00:00:e8:77:50:06 (AcctonTe_77:50:06) Source: 00:e0:18:80:4c:8f (AsustekC_80:4c:8f) Type: IP (0x0800) Trailer: 00000000000000000000000000000000... ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Internet Protocol, Src Addr: 192.168.100.30 (192.168.100.30), Dst Addr: 192.168.100.26 (192.168.100.26) Version: 4 Header length: 20 bytes Differentiated Services Field: 0x00 (DSCP 0x00: Default; ECN: 0x00) 0000 00.. = Differentiated Services Codepoint: Default (0x00) .... ..0. = ECN-Capable Transport (ECT): 0 .... ...0 = ECN-CE: 0 Total Length: 28 Identification: 0xa67e (42622) Flags: 0x00 .0.. = Don't fragment: Not set ..0. = More fragments: Not set Fragment offset: 0 Time to live: 254 Protocol: UDP (0x11) Header checksum: 0xccc8 (correct) Source: 192.168.100.30 (192.168.100.30) Destination: 192.168.100.26 (192.168.100.26) User Datagram Protocol, Src Port: 5070 (5070), Dst Port: 5064 (5064) Source port: 5070 (5070) Destination port: 5064 (5064) Length: 8 Checksum: 0x8ebe (correct) ------------ end -------------------------------- Regards, Zen
