Date: Fri, 04 Apr 2008 01:34:07 +0200 From: Ivan Voras <ivoras@freebsd.org> To: freebsd-net@freebsd.org Subject: Trouble with IPFW or TCP? Message-ID: <ft3phn$ai3$1@ger.gmane.org>
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0 0 deny ip from any to any Generate syslog messages like these: Apr 4 01:02:06 my.ip kernel: ipfw: 65400 Deny TCP xx.xx.xx.xx:60725=20 my.ip.my.ip:443 in via em0 Apr 4 01:02:06 my.ip kernel: ipfw: 65400 Deny TCP xx.xx.xx.xx:57387=20 my.ip.my.ip:443 in via em0 Apr 4 01:02:06 my.ip kernel: ipfw: 65400 Deny TCP xx.xx.xx.xx:57387=20 my.ip.my.ip:443 in via em0 Apr 4 01:02:06 my.ip kernel: ipfw: 65400 Deny TCP xx.xx.xx.xx:61998=20 my.ip.my.ip:443 in via em0 Apr 4 01:02:06 my.ip kernel: ipfw: 65400 Deny TCP xx.xx.xx.xx:61998=20 my.ip.my.ip:443 in via em0 Apr 4 01:02:06 my.ip kernel: ipfw: 65400 Deny TCP xx.xx.xx.xx:64288=20 my.ip.my.ip:443 in via em0 Apr 4 01:02:06 my.ip kernel: ipfw: 65400 Deny TCP xx.xx.xx.xx:64288=20 my.ip.my.ip:443 in via em0 Apr 4 01:02:06 my.ip kernel: ipfw: 65400 Deny TCP xx.xx.xx.xx:50212=20 my.ip.my.ip:443 in via em0 Apr 4 01:02:06 my.ip kernel: ipfw: 65400 Deny TCP xx.xx.xx.xx:50212=20 my.ip.my.ip:443 in via em0 Apr 4 01:02:06 my.ip kernel: ipfw: 65400 Deny TCP xx.xx.xx.xx:58149=20 my.ip.my.ip:443 in via em0 Apr 4 01:02:06 my.ip kernel: ipfw: 65400 Deny TCP xx.xx.xx.xx:58149=20 my.ip.my.ip:443 in via em0 Apr 4 01:02:13 my.ip kernel: ipfw: 65400 Deny TCP yy.yy.yy.yy:61919=20 my.ip.my.ip:443 in via em0 Apr 4 01:02:13 my.ip kernel: ipfw: 65400 Deny TCP yy.yy.yy.yy:61919=20 my.ip.my.ip:443 in via em0 Apr 4 01:02:13 my.ip kernel: ipfw: 65400 Deny TCP yy.yy.yy.yy:56792=20 my.ip.my.ip:443 in via em0 Apr 4 01:02:13 my.ip kernel: ipfw: 65400 Deny TCP yy.yy.yy.yy:56792=20 my.ip.my.ip:443 in via em0 Apr 4 01:02:14 my.ip kernel: ipfw: 65400 Deny TCP yy.yy.yy.yy:53795=20 my.ip.my.ip:443 in via em0 Apr 4 01:02:16 my.ip kernel: ipfw: 65400 Deny TCP zz.zz.zz.zz:58314=20 my.ip.my.ip:443 in via em0 Apr 4 01:02:16 my.ip kernel: ipfw: 65400 Deny TCP zz.zz.zz.zz:63204=20 my.ip.my.ip:443 in via em0 Apr 4 01:02:16 my.ip kernel: ipfw: 65400 Deny TCP zz.zz.zz.zz:58314=20 my.ip.my.ip:443 in via em0 Apr 4 01:02:16 my.ip kernel: ipfw: 65400 Deny TCP zz.zz.zz.zz:52125=20 my.ip.my.ip:443 in via em0 Apr 4 01:02:16 my.ip kernel: ipfw: 65400 Deny TCP zz.zz.zz.zz:53386=20 my.ip.my.ip:443 in via em0 Apr 4 01:02:16 my.ip kernel: ipfw: 65400 Deny TCP zz.zz.zz.zz:63626=20 my.ip.my.ip:443 in via em0 Apr 4 01:02:16 my.ip kernel: ipfw: 65400 Deny TCP zz.zz.zz.zz:63204=20 my.ip.my.ip:443 in via em0 Apr 4 01:02:16 my.ip kernel: ipfw: 65400 Deny TCP zz.zz.zz.zz:51376=20 my.ip.my.ip:443 in via em0 Apr 4 01:02:16 my.ip kernel: ipfw: 65400 Deny TCP zz.zz.zz.zz:61880=20 my.ip.my.ip:443 in via em0 Apr 4 01:02:16 my.ip kernel: ipfw: 65400 Deny TCP zz.zz.zz.zz:49319=20 my.ip.my.ip:443 in via em0 Apr 4 01:02:16 my.ip kernel: ipfw: 65400 Deny TCP zz.zz.zz.zz:52125=20 my.ip.my.ip:443 in via em0 Apr 4 01:02:16 my.ip kernel: ipfw: 65400 Deny TCP zz.zz.zz.zz:62381=20 my.ip.my.ip:443 in via em0 Apr 4 01:02:16 my.ip kernel: ipfw: 65400 Deny TCP zz.zz.zz.zz:53386=20 my.ip.my.ip:443 in via em0 Apr 4 01:02:16 my.ip kernel: ipfw: 65400 Deny TCP zz.zz.zz.zz:63626=20 my.ip.my.ip:443 in via em0 Apr 4 01:02:16 my.ip kernel: ipfw: 65400 Deny TCP zz.zz.zz.zz:51376=20 my.ip.my.ip:443 in via em0 Apr 4 01:02:16 my.ip kernel: ipfw: 65400 Deny TCP zz.zz.zz.zz:54109=20 my.ip.my.ip:443 in via em0 Apr 4 01:02:16 my.ip kernel: ipfw: 65400 Deny TCP zz.zz.zz.zz:56945=20 my.ip.my.ip:443 in via em0 Apr 4 01:02:16 my.ip kernel: ipfw: 65400 Deny TCP zz.zz.zz.zz:61880=20 my.ip.my.ip:443 in via em0 Apr 4 01:02:16 my.ip kernel: ipfw: 65400 Deny TCP zz.zz.zz.zz:50800=20 my.ip.my.ip:443 in via em0 Apr 4 01:02:16 my.ip kernel: ipfw: 65400 Deny TCP zz.zz.zz.zz:49319=20 my.ip.my.ip:443 in via em0 Apr 4 01:02:16 my.ip kernel: ipfw: 65400 Deny TCP zz.zz.zz.zz:53347=20 my.ip.my.ip:443 in via em0 Apr 4 01:02:16 my.ip kernel: ipfw: 65400 Deny TCP zz.zz.zz.zz:58735=20 my.ip.my.ip:443 in via em0 Apr 4 01:02:16 my.ip kernel: ipfw: 65400 Deny TCP zz.zz.zz.zz:58732=20 my.ip.my.ip:443 in via em0 Apr 4 01:02:16 my.ip kernel: ipfw: 65400 Deny TCP zz.zz.zz.zz:62381=20 my.ip.my.ip:443 in via em0 Apr 4 01:02:16 my.ip kernel: ipfw: 65400 Deny TCP zz.zz.zz.zz:56837=20 my.ip.my.ip:443 in via em0 Apr 4 01:02:16 my.ip kernel: ipfw: 65400 Deny TCP zz.zz.zz.zz:54109=20 my.ip.my.ip:443 in via em0 Apr 4 01:02:16 my.ip kernel: ipfw: 65400 Deny TCP zz.zz.zz.zz:65318=20 my.ip.my.ip:443 in via em0 Apr 4 01:02:16 my.ip kernel: ipfw: 65400 Deny TCP zz.zz.zz.zz:56945=20 my.ip.my.ip:443 in via em0 Apr 4 01:02:16 my.ip kernel: ipfw: 65400 Deny TCP zz.zz.zz.zz:50800=20 my.ip.my.ip:443 in via em0 Apr 4 01:02:16 my.ip kernel: ipfw: 65400 Deny TCP zz.zz.zz.zz:53347=20 my.ip.my.ip:443 in via em0 Apr 4 01:02:16 my.ip kernel: ipfw: 65400 Deny TCP zz.zz.zz.zz:58735=20 my.ip.my.ip:443 in via em0 Apr 4 01:02:16 my.ip kernel: ipfw: 65400 Deny TCP zz.zz.zz.zz:58732=20 my.ip.my.ip:443 in via em0 Apr 4 01:02:16 my.ip kernel: ipfw: 65400 Deny TCP zz.zz.zz.zz:56837=20 my.ip.my.ip:443 in via em0 Apr 4 01:02:16 my.ip kernel: ipfw: 65400 Deny TCP zz.zz.zz.zz:65318=20 my.ip.my.ip:443 in via em0 ? I can connect with plain telnet from the reported addresses without=20 problems. One thing that is suspicious is that the messages come in=20 these bursts (which I can't explain) but the Apache's listen backlog=20 should handle those. In any case, I don't think they are connection=20 requests: Here's output of "tcpdump -v host xx.xx.xx.xx and port 443": 01:13:07.654677 IP (tos 0x0, ttl 58, id 54089, offset 0, flags [none],=20 proto TCP (6), length 40) xx.xx.xx.xx.58789 > my.ip.my.ip.https: .,=20 cksum 0x54ca (correct), ack 3708282724 win 0 01:13:07.654764 IP (tos 0x0, ttl 58, id 54095, offset 0, flags [none],=20 proto TCP (6), length 40) xx.xx.xx.xx.61579 > my.ip.my.ip.https: .,=20 cksum 0xf60d (correct), ack 610863831 win 0 01:13:07.654810 IP (tos 0x0, ttl 58, id 54099, offset 0, flags [none],=20 proto TCP (6), length 40) xx.xx.xx.xx.61852 > my.ip.my.ip.https: .,=20 cksum 0xab18 (correct), ack 1491048554 win 0 01:13:07.654854 IP (tos 0x0, ttl 58, id 54103, offset 0, flags [none],=20 proto TCP (6), length 40) xx.xx.xx.xx.63950 > my.ip.my.ip.https: .,=20 cksum 0x1e51 (correct), ack 2955921131 win 0 01:13:07.654897 IP (tos 0x0, ttl 58, id 54107, offset 0, flags [none],=20 proto TCP (6), length 40) xx.xx.xx.xx.53299 > my.ip.my.ip.https: .,=20 cksum 0xa141 (correct), ack 2339864417 win 0 01:13:07.654940 IP (tos 0x0, ttl 58, id 54121, offset 0, flags [none],=20 proto TCP (6), length 40) xx.xx.xx.xx.50521 > my.ip.my.ip.https: .,=20 cksum 0x2c55 (correct), ack 216576745 win 0 01:13:07.654984 IP (tos 0x0, ttl 58, id 54123, offset 0, flags [DF],=20 proto TCP (6), length 52) xx.xx.xx.xx.58789 > my.ip.my.ip.https: .,=20 cksum 0x882d (correct), ack 1 win 33304 <nop,nop,timestamp 140692997=20 4077078528> 01:13:07.655026 IP (tos 0x0, ttl 58, id 54126, offset 0, flags [DF],=20 proto TCP (6), length 52) xx.xx.xx.xx.61579 > my.ip.my.ip.https: .,=20 cksum 0x0617 (correct), ack 1 win 33304 <nop,nop,timestamp 140692997=20 3172245833> 01:13:07.655069 IP (tos 0x0, ttl 58, id 54128, offset 0, flags [DF],=20 proto TCP (6), length 52) xx.xx.xx.xx.61852 > my.ip.my.ip.https: .,=20 cksum 0x7006 (correct), ack 1 win 33304 <nop,nop,timestamp 140692997=20 3472415360> 01:13:07.655112 IP (tos 0x0, ttl 58, id 54130, offset 0, flags [DF],=20 proto TCP (6), length 52) xx.xx.xx.xx.63950 > my.ip.my.ip.https: .,=20 cksum 0x7ade (correct), ack 1 win 33304 <nop,nop,timestamp 140692997=20 415365400> 01:13:07.655155 IP (tos 0x0, ttl 58, id 54132, offset 0, flags [DF],=20 proto TCP (6), length 52) xx.xx.xx.xx.53299 > my.ip.my.ip.https: .,=20 cksum 0x4087 (correct), ack 1 win 33304 <nop,nop,timestamp 140692997=20 2999393370> 01:13:07.655197 IP (tos 0x0, ttl 58, id 54139, offset 0, flags [DF],=20 proto TCP (6), length 52) xx.xx.xx.xx.50521 > my.ip.my.ip.https: .,=20 cksum 0x13e0 (correct), ack 1 win 33304 <nop,nop,timestamp 140692997=20 3427580559> There are no SYNs here, so it looks to me like something mid-traffic. For addresses such as those in the ipfw log, I see several messages like:= Mar 24 17:00:01 my.ip kernel: TCP: [xx.xx.xx.xx]:64714 to=20 [my.ip.my.ip]:443 tcpflags 0x18<PUSH,ACK>; tcp_do_segment: FIN_WAIT_2:=20 Received 198 bytes of data after socket was closed, sending RST and=20 removing tcpcb Mar 24 17:10:57 my.ip kernel: 6110>ipfw: 65400 Deny TCP=20 xx.xx.xx.xx:58213 my.ip.my.ip:443 in via em0 Mar 25 00:00:05 my.ip kernel: TCP: [xx.xx.xx.xx]:52233 to=20 [my.ip.my.ip]:443 tcpflags 0x10<ACK>; syncache_expand: Segment failed=20 SYNCOOKIE authentication, segment rejected (probably spoofed) Mar 25 01:45:05 my.ip kernel: TCP: [xx.xx.xx.xx]:51120 to=20 [my.ip.my.ip]:443 tcpflags 0x10<ACK>; syncache_expand: Segment failed=20 SYNCOOKIE authentication, segment rejected (probably spoofed) Mar 25 01:45:05 my.ip kernel: TCP: [xx.xx.xx.xx]:51120 to=20 [my.ip.my.ip]:443 tcpflags 0x10<ACK>; syncache_expand: Segment failed=20 SYNCOOKIE authentication, segment rejected (probably spoofed) Mar 25 14:00:09 my.ip kernel: TCP: [xx.xx.xx.xx]:55665 to=20 [my.ip.my.ip]:443 tcpflags 0x10<ACK>; syncache_expand: Segment failed=20 SYNCOOKIE authentication, segment rejected (probably spoofed) Mar 25 14:00:09 my.ip kernel: TCP: [xx.xx.xx.xx]:55665 to=20 [my.ip.my.ip]:443 tcpflags 0x10<ACK>; syncache_expand: Segment failed=20 SYNCOOKIE authentication, segment rejected (probably spoofed) Mar 25 17:00:00 my.ip kernel: TCP: [xx.xx.xx.xx]:60048 to=20 [my.ip.my.ip]:443 tcpflags 0x18<PUSH,ACK>; tcp_do_segment: FIN_WAIT_1:=20 Received 346 bytes of data after socket was closed, sending RST and=20 removing tcpcb Mar 25 17:00:00 my.ip kernel: TCP: [xx.xx.xx.xx]:60048 to=20 [my.ip.my.ip]:443 tcpflags 0x11<FIN,ACK>; syncache_expand: Segment=20 failed SYNCOOKIE authentication, segment rejected (probably spoofed) Mar 25 23:00:01 my.ip kernel: TCP: [xx.xx.xx.xx]:50205 to=20 [my.ip.my.ip]:443 tcpflags 0x18<PUSH,ACK>; tcp_do_segment: FIN_WAIT_1:=20 Received 346 bytes of data after socket was closed, sending RST and=20 removing tcpcb Mar 25 23:00:01 my.ip kernel: TCP: [xx.xx.xx.xx]:50205 to=20 [my.ip.my.ip]:443 tcpflags 0x11<FIN,ACK>; syncache_expand: Segment=20 failed SYNCOOKIE authentication, segment rejected (probably spoofed) Mar 26 00:38:49 my.ip kernel: <a10>ipfw: 65400 Deny TCP=20 xx.xx.xx.xx:61129 my.ip.my.ip:443 in via em0 Apr 2 09:00:01 my.ip kernel: TCP: [xx.xx.xx.xx]:57248 to=20 [my.ip.my.ip]:443 tcpflags 0x18<PUSH,ACK>; tcp_do_segment: FIN_WAIT_1:=20 Received 330 bytes of data after socket was closed, sending RST and=20 removing tcpcb Apr 2 09:00:01 my.ip kernel: TCP: [xx.xx.xx.xx]:57248 to=20 [my.ip.my.ip]:443 tcpflags 0x11<FIN,ACK>; syncache_expand: Segment=20 failed SYNCOOKIE authentication, segment rejected (probably spoofed) But these messages do *not* occur when the ipfw log and tcpdump record=20 the above described behaviour so it might not be connected. The machine at my.ip is running 7.0-RELEASE i386, the rest are a set of=20 machines that send trivial periodic (every 15 minutes) HTTPS messages to = this machine. In this set most are 6.2 or 6.3, mixed i386 and amd64. The one 7-STABLE=20 machine that does the same thing doesn't generate the behaviour=20 described above so it might be something specific to when 6.x machines=20 talk to 7.x. Was there a bug like that in 6.x? --------------enig1FB290221A96A9CD76AF169F Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.5 (MingW32) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFH9Wl1ldnAQVacBcgRAnwfAJ9jkCiQbHFCari7u2iR/FseGAlbeQCfSF7y RpnNQrpzFeYeXTGhcg6UBGg= =WLHk -----END PGP SIGNATURE----- --------------enig1FB290221A96A9CD76AF169F--
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