HELP! weird tcp problem
Maksim Yevmenkin
maksim.yevmenkin at gmail.com
Mon Jun 18 18:08:43 UTC 2007
All,
after upgrading to -current this weekend i started to have weird tcp
problems. first of all tcp connections from initiated from firefox
and/or thunderbird no longer work. please see info below
====
beetle% uname -a
FreeBSD beetle.level3.com 7.0-CURRENT FreeBSD 7.0-CURRENT #91: Sat Jun
16 13:33:48 PDT 2007
root at beetle.level3.com:/usr/obj/usr/src/sys/GENERIC i386
====
beetle% sysctl net.inet.tcp
net.inet.tcp.rfc1323: 1
net.inet.tcp.mssdflt: 512
net.inet.tcp.keepidle: 120000
net.inet.tcp.keepintvl: 75000
net.inet.tcp.sendspace: 32768
net.inet.tcp.recvspace: 65536
net.inet.tcp.keepinit: 75000
net.inet.tcp.delacktime: 100
net.inet.tcp.v6mssdflt: 1024
net.inet.tcp.hostcache.purge: 0
net.inet.tcp.hostcache.prune: 300
net.inet.tcp.hostcache.expire: 3600
net.inet.tcp.hostcache.count: 1
net.inet.tcp.hostcache.bucketlimit: 30
net.inet.tcp.hostcache.hashsize: 512
net.inet.tcp.hostcache.cachelimit: 15360
net.inet.tcp.recvbuf_max: 262144
net.inet.tcp.recvbuf_inc: 16384
net.inet.tcp.recvbuf_auto: 1
net.inet.tcp.insecure_rst: 0
net.inet.tcp.rfc3390: 1
net.inet.tcp.rfc3042: 1
net.inet.tcp.drop_synfin: 0
net.inet.tcp.delayed_ack: 1
net.inet.tcp.blackhole: 0
net.inet.tcp.log_in_vain: 0
net.inet.tcp.sendbuf_max: 262144
net.inet.tcp.sendbuf_inc: 8192
net.inet.tcp.sendbuf_auto: 1
net.inet.tcp.tso: 1
net.inet.tcp.newreno: 1
net.inet.tcp.local_slowstart_flightsize: 4
net.inet.tcp.slowstart_flightsize: 1
net.inet.tcp.path_mtu_discovery: 1
net.inet.tcp.reass.overflows: 0
net.inet.tcp.reass.maxqlen: 48
net.inet.tcp.reass.cursegments: 0
net.inet.tcp.reass.maxsegments: 1600
net.inet.tcp.sack.globalholes: 0
net.inet.tcp.sack.globalmaxholes: 65536
net.inet.tcp.sack.maxholes: 128
net.inet.tcp.sack.enable: 1
net.inet.tcp.inflight.stab: 20
net.inet.tcp.inflight.max: 1073725440
net.inet.tcp.inflight.min: 6144
net.inet.tcp.inflight.rttthresh: 10
net.inet.tcp.inflight.debug: 0
net.inet.tcp.inflight.enable: 1
net.inet.tcp.isn_reseed_interval: 0
net.inet.tcp.icmp_may_rst: 1
net.inet.tcp.pcbcount: 8
net.inet.tcp.do_tcpdrain: 1
net.inet.tcp.tcbhashsize: 512
net.inet.tcp.minmss: 216
net.inet.tcp.syncache.rst_on_sock_fail: 1
net.inet.tcp.syncache.rexmtlimit: 3
net.inet.tcp.syncache.hashsize: 512
net.inet.tcp.syncache.count: 0
net.inet.tcp.syncache.cachelimit: 15360
net.inet.tcp.syncache.bucketlimit: 30
net.inet.tcp.syncookies_only: 0
net.inet.tcp.syncookies: 1
net.inet.tcp.timer_race: 0
net.inet.tcp.finwait2_timeout: 60000
net.inet.tcp.fast_finwait2_recycle: 0
net.inet.tcp.always_keepalive: 1
net.inet.tcp.rexmit_slop: 200
net.inet.tcp.rexmit_min: 3
net.inet.tcp.msl: 30000
net.inet.tcp.nolocaltimewait: 0
net.inet.tcp.maxtcptw: 2465
====
beetle% ifconfig -a
bge0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
options=9b<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,VLAN_HWCSUM>
ether 00:11:43:54:22:c9
inet 10.12.163.152 netmask 0xffffff80 broadcast 10.12.163.255
media: Ethernet 100baseTX <full-duplex>
status: active
plip0: flags=108810<POINTOPOINT,SIMPLEX,MULTICAST,NEEDSGIANT> metric 0 mtu 1500
lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> metric 0 mtu 16384
inet6 fe80::1%lo0 prefixlen 64 scopeid 0x3
inet6 ::1 prefixlen 128
inet 127.0.0.1 netmask 0xff000000
====
beetle% netstat -rn
Routing tables
Internet:
Destination Gateway Flags Refs Use Netif Expire
default 10.12.163.129 UGS 0 107 bge0
10.12.163.128/25 link#1 UC 0 0 bge0
10.12.163.129 00:1a:6c:74:2b:39 UHLW 2 0 bge0 1143
10.12.163.151 00:16:d4:9e:a5:b0 UHLW 1 150 bge0 1147
10.12.163.199 08:00:20:b5:8f:92 UHLW 2 2 bge0 861
127.0.0.1 127.0.0.1 UH 0 94 lo0
192.168.1.0/24 10.12.163.199 UGS 0 2 bge0
Internet6:
Destination Gateway Flags
Netif Expire
::1 ::1 UHL lo0
fe80::%lo0/64 fe80::1%lo0 U lo0
fe80::1%lo0 link#3 UHL lo0
ff01:3::/32 fe80::1%lo0 UC lo0
ff02::%lo0/32 fe80::1%lo0 UC lo0
====
beetle# ipfw show
00100 188 21618 allow ip from any to any via lo0
00200 0 0 deny ip from any to 127.0.0.0/8
00300 0 0 deny ip from 127.0.0.0/8 to any
65000 1103 163395 allow ip from any to any
65535 0 0 deny ip from any to any
===
now tcpdump output when i try to go to http://www.yahoo.com/ from firefox
beetle# tcpdump -n -vv -s0 -S -X -i bge0 port 80
tcpdump: listening on bge0, link-type EN10MB (Ethernet), capture size
65535 bytes
10:34:47.217922 IP (tos 0x0, ttl 64, id 459, offset 0, flags [DF],
proto: TCP (6), length: 60, bad cksum 0 (->5c59)!) 10.12.163.152.49879
> 209.191.93.52.80: S, cksum 0xdcc6 (incorrect (-> 0x7442),
3892604697:3892604697(0) win 65535 <mss 1460,nop,wscale
8,sackOK,timestamp 384217 0>
0x0000: 4500 003c 01cb 4000 4006 0000 0a0c a398 E..<.. at .@.......
0x0010: d1bf 5d34 c2d7 0050 e804 6f19 0000 0000 ..]4...P..o.....
0x0020: a002 ffff dcc6 0000 0204 05b4 0103 0308 ................
0x0030: 0402 080a 0005 dcd9 0000 0000 ............
10:34:47.273178 IP (tos 0x0, ttl 51, id 60635, offset 0, flags [DF],
proto: TCP (6), length: 64) 209.191.93.52.80 > 10.12.163.152.49879: S,
cksum 0x2b67 (correct), 112085153:112085153(0) ack 3892604698 win
65535 <mss 1460,nop,wscale 1,nop,nop,timestamp 2476823771
384217,sackOK,eol>
0x0000: 4500 0040 ecdb 4000 3306 7e44 d1bf 5d34 E.. at ..@.3.~D..]4
0x0010: 0a0c a398 0050 c2d7 06ae 48a1 e804 6f1a .....P....H...o.
0x0020: b012 ffff 2b67 0000 0204 05b4 0103 0301 ....+g..........
0x0030: 0101 080a 93a1 54db 0005 dcd9 0402 0000 ......T.........
10:34:47.273219 IP (tos 0x0, ttl 64, id 460, offset 0, flags [DF],
proto: TCP (6), length: 40, bad cksum 0 (->5c6c)!) 10.12.163.152.49879
> 209.191.93.52.80: R, cksum 0xdcb2 (incorrect (-> 0xb901),
3892604698:3892604698(0) win 0
0x0000: 4500 0028 01cc 4000 4006 0000 0a0c a398 E..(.. at .@.......
0x0010: d1bf 5d34 c2d7 0050 e804 6f1a 0000 0000 ..]4...P..o.....
0x0020: 5004 0000 dcb2 0000 0000 0000 0000 P.............
^C
3 packets captured
255 packets received by filter
0 packets dropped by kernel
as you can see my laptop simply sends reset after syn+ack is recevied
from the peer.
====
now tcpdump output when i do "telnet www.yahoo.com 80". as you can see
everything seems to work.
beetle# tcpdump -n -vv -s0 -S -X -i bge0 port 80
tcpdump: listening on bge0, link-type EN10MB (Ethernet), capture size
65535 bytes
10:35:15.462718 IP (tos 0x10, ttl 64, id 478, offset 0, flags [DF],
proto: TCP (6), length: 60, bad cksum 0 (->5c36)!) 10.12.163.152.56333
> 209.191.93.52.80: S, cksum 0xdcc6 (incorrect (-> 0x84e9),
1764906425:1764906425(0) win 65535 <mss 1460,nop,wscale
8,sackOK,timestamp 412462 0>
0x0000: 4510 003c 01de 4000 4006 0000 0a0c a398 E..<.. at .@.......
0x0010: d1bf 5d34 dc0d 0050 6932 55b9 0000 0000 ..]4...Pi2U.....
0x0020: a002 ffff dcc6 0000 0204 05b4 0103 0308 ................
0x0030: 0402 080a 0006 4b2e 0000 0000 ......K.....
10:35:15.517030 IP (tos 0x0, ttl 51, id 11180, offset 0, flags [DF],
proto: TCP (6), length: 64) 209.191.93.52.80 > 10.12.163.152.56333: S,
cksum 0x3539 (correct), 1090115527:1090115527(0) ack 1764906426 win
65535 <mss 1460,nop,wscale 1,nop,nop,timestamp 2478346791
412462,sackOK,eol>
0x0000: 4500 0040 2bac 4000 3306 3f74 d1bf 5d34 E.. at +.@.3.?t..]4
0x0010: 0a0c a398 0050 dc0d 40f9 d7c7 6932 55ba .....P.. at ...i2U.
0x0020: b012 ffff 3539 0000 0204 05b4 0103 0301 ....59..........
0x0030: 0101 080a 93b8 9227 0006 4b2e 0402 0000 .......'..K.....
10:35:15.517077 IP (tos 0x10, ttl 64, id 479, offset 0, flags [DF],
proto: TCP (6), length: 52, bad cksum 0 (->5c3d)!) 10.12.163.152.56333
> 209.191.93.52.80: ., cksum 0xdcbe (incorrect (-> 0x73ca),
1764906426:1764906426(0) ack 1090115528 win 260 <nop,nop,timestamp
412516 2478346791>
0x0000: 4510 0034 01df 4000 4006 0000 0a0c a398 E..4.. at .@.......
0x0010: d1bf 5d34 dc0d 0050 6932 55ba 40f9 d7c8 ..]4...Pi2U. at ...
0x0020: 8010 0104 dcbe 0000 0101 080a 0006 4b64 ..............Kd
0x0030: 93b8 9227 ...'
10:35:20.564276 IP (tos 0x10, ttl 64, id 482, offset 0, flags [DF],
proto: TCP (6), length: 52, bad cksum 0 (->5c3a)!) 10.12.163.152.56333
> 209.191.93.52.80: F, cksum 0xdcbe (incorrect (-> 0x6012),
1764906426:1764906426(0) ack 1090115528 win 260 <nop,nop,timestamp
417563 2478346791>
0x0000: 4510 0034 01e2 4000 4006 0000 0a0c a398 E..4.. at .@.......
0x0010: d1bf 5d34 dc0d 0050 6932 55ba 40f9 d7c8 ..]4...Pi2U. at ...
0x0020: 8011 0104 dcbe 0000 0101 080a 0006 5f1b .............._.
0x0030: 93b8 9227 ...'
10:35:20.618435 IP (tos 0x0, ttl 51, id 18390, offset 0, flags [DF],
proto: TCP (6), length: 52) 209.191.93.52.80 > 10.12.163.152.56333: .,
cksum 0xcb10 (correct), 1090115528:1090115528(0) ack 1764906427 win
33304 <nop,nop,timestamp 2478351892 417563>
0x0000: 4500 0034 47d6 4000 3306 2356 d1bf 5d34 E..4G. at .3.#V..]4
0x0010: 0a0c a398 0050 dc0d 40f9 d7c8 6932 55bb .....P.. at ...i2U.
0x0020: 8010 8218 cb10 0000 0101 080a 93b8 a614 ................
0x0030: 0006 5f1b .._.
10:35:20.618588 IP (tos 0x0, ttl 51, id 18391, offset 0, flags [DF],
proto: TCP (6), length: 52) 209.191.93.52.80 > 10.12.163.152.56333: F,
cksum 0xcb0e (correct), 1090115528:1090115528(0) ack 1764906427 win
33304 <nop,nop,timestamp 2478351893 417563>
0x0000: 4500 0034 47d7 4000 3306 2355 d1bf 5d34 E..4G. at .3.#U..]4
0x0010: 0a0c a398 0050 dc0d 40f9 d7c8 6932 55bb .....P.. at ...i2U.
0x0020: 8011 8218 cb0e 0000 0101 080a 93b8 a615 ................
0x0030: 0006 5f1b .._.
10:35:20.618623 IP (tos 0x10, ttl 64, id 483, offset 0, flags [DF],
proto: TCP (6), length: 52, bad cksum 0 (->5c39)!) 10.12.163.152.56333
> 209.191.93.52.80: ., cksum 0xdcbe (incorrect (-> 0x4bed),
1764906427:1764906427(0) ack 1090115529 win 260 <nop,nop,timestamp
417617 2478351893>
0x0000: 4510 0034 01e3 4000 4006 0000 0a0c a398 E..4.. at .@.......
0x0010: d1bf 5d34 dc0d 0050 6932 55bb 40f9 d7c9 ..]4...Pi2U. at ...
0x0020: 8010 0104 dcbe 0000 0101 080a 0006 5f51 .............._Q
0x0030: 93b8 a615 ....
^C
7 packets captured
201 packets received by filter
0 packets dropped by kernel
does anyone knows what is going on here?!
thanks,
max
p.s. everything was working just fine prior to upgrade this weekend
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