IPSec tcp session stalling
Volker
volker at vwsoft.com
Sat Oct 22 16:23:55 PDT 2005
Michael,
I not that sure if I'm right in checking what you suggested but when
trying to do ping hostB from hostA with oversized packets through the
IPSec tunnel by:
# ping -c 10 -s 12000 10.128.6.1
I'm getting replies easily.
While doing that and tcpdump'ing the gif interface, I'm seeing the
fragmented packets coming in properly.
If that's a reliable check for MTU than the problem should not be MTU
related. Is there any other way to check MTU problems by using `ping'?
Thanks,
Volker
On 2005-10-22 20:16, Michael VInce wrote:
> Try sending different sized pings or other packet size control utils to
> really make sure its not MTU related.
> Maybe there is an upstream router thats blocking ICMP fragment packets,
> have you ever seen them? try forcing the creation of some.
>
> Mike
>
> Volker wrote:
>
>> Still having the same problem with an IPSec tunnel between FreeBSD 5.4R
>> hosts.
>>
>> Problem description:
>> scp session tries to transfer a large file through an IPSec tunnel. The
>> file is being transmitted but scp says 'stalled' after 56K (49152 bytes
>> file size). The IPSec tunnel itself is still up even after the scp
>> abort. Other tcp sessions break, too when sending too much traffic
>> through the tunnel.
>>
>> I've taken a closer look to it and tried to get something useful out of
>> the tcpdump but I'm unable to see any errors or I'm misinterpreting
>> something.
>>
>> The connection looks like:
>>
>> extIP: A.B.C.D
>> extIP: E.F.G.H
>> host A ------------------ (internet) ------------------ host B
>> tunnelIP: 10.128.1.6 tunnelIP:
>> 10.128.6.1
>>
>> host A just has an external interface (em1) connected to a leased line
>> with a fixed IP address (IP-addr A.B.C.D).
>> host B has an S-DSL connection at xl0, PPPoE at ng0 (IP-addr. E.F.G.H).
>>
>> Both hosts are using gif for the IPSec tunnel.
>>
>> The routing tables (netstat -rnWf inet) are looking good and IMHO the
>> MTU is fine.
>>
>> host A:
>> em1: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
>> options=b<RXCSUM,TXCSUM,VLAN_MTU>
>> inet A.B.C.D netmask 0xfffffff8 broadcast A.B.C.z
>> ether 00:c0:9f:46:ec:c7
>> media: Ethernet autoselect (100baseTX <full-duplex>)
>> status: active
>> gif6: flags=8051<UP,POINTOPOINT,RUNNING,MULTICAST> mtu 1280
>> tunnel inet A.B.C.D --> E.F.G.H
>> inet 10.128.1.6 --> 10.128.6.1 netmask 0xffffffff
>> inet6 fe80::2c0:9fff:fe46:ecc6%gif6 prefixlen 64 scopeid 0x4
>>
>> Routing tables (shortened)
>> Destination Gateway Flags Refs Use Mtu
>> Netif Expire
>> default A.B.C.x UGS 2 516686 1500 em1
>> 10.128.1.6 127.0.0.1 UH 0 14
>> 16384 lo0
>> 10.128.6.1 10.128.1.6 UH 0 6017
>> 1280 gif6
>> 127.0.0.1 127.0.0.1 UH 0 31633
>> 16384 lo0
>> A.B.C.x/29 link#2 UC 0 0 1500 em1
>> A.B.C.D 00:c0:9f:46:ec:c7 UHLW 0 112 1500 lo0
>>
>> On host B the interfaces and routing tables are looking like:
>> xl0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
>> options=8<VLAN_MTU>
>> inet 0.0.0.0 netmask 0xff000000 broadcast 0.255.255.255
>> inet6 fe80::260:8ff:fe6c:e73c%xl0 prefixlen 64 scopeid 0x1
>> ether 00:60:08:6c:e7:3c
>> media: Ethernet 10baseT/UTP (10baseT/UTP <half-duplex>)
>> status: active
>> gif1: flags=8051<UP,POINTOPOINT,RUNNING,MULTICAST> mtu 1280
>> tunnel inet E.F.G.H --> A.B.C.D
>> inet6 fe80::260:8ff:fe6c:e73c%gif1 prefixlen 64 scopeid 0x4
>> inet 10.128.6.1 --> 10.128.1.6 netmask 0xffffffff
>> ng0: flags=88d1<UP,POINTOPOINT,RUNNING,NOARP,SIMPLEX,MULTICAST> mtu 1456
>> inet E.F.G.H --> 217.5.98.186 netmask 0xffffffff
>>
>> Routing tables (shortened)
>> Destination Gateway Flags Refs Use Mtu
>> Netif Expire
>> 0 link#1 UC 0 0 1500
>> xl0 =>
>> default 217.5.98.186 UGS 1 38474
>> 1456 ng0
>> 10.128.1.6 10.128.6.1 UH 4 2196
>> 1280 gif1
>> 127.0.0.1 127.0.0.1 UH 0 80424
>> 16384 lo0
>> 217.5.98.186 E.F.G.H UH 1 0 1456 ng0
>> E.F.G.H lo0 UHS 0 0 16384 lo0
>>
>> While trying to fetch a file by scp on host A (receiver) from host B
>> (sender), I captured the following tcpdump on host B:
>>
>> tcpdump -netttvvi gif1:
>>
>>
>>> 000023 AF 2 1280: IP (tos 0x8, ttl 64, id 13202, offset 0, flags
>>> [none], length: 1280) 10.128.6.1.22 > 10.128.1.6.53160: .
>>> 43864:45092(1228) ack 1330 win 33156 <nop,nop,timestamp 481770567
>>> 565002838>
>>> 000207 AF 2 1280: IP (tos 0x8, ttl 64, id 52187, offset 0, flags
>>> [none], length: 1280) 10.128.6.1.22 > 10.128.1.6.53160: .
>>> 45092:46320(1228) ack 1330 win 33156 <nop,nop,timestamp 481770567
>>> 565002838>
>>> 000220 AF 2 1280: IP (tos 0x8, ttl 64, id 33774, offset 0, flags
>>> [none], length: 1280) 10.128.6.1.22 > 10.128.1.6.53160: .
>>> 46320:47548(1228) ack 1330 win 33156 <nop,nop,timestamp 481770568
>>> 565002838>
>>> 003524 AF 2 52: IP (tos 0x8, ttl 64, id 42063, offset 0, flags
>>> [none], length: 52) 10.128.1.6.53160 > 10.128.6.1.22: . [tcp sum ok]
>>> 1330:1330(0) ack 38952 win 33156 <nop,nop,timestamp 565002844 481770524>
>>> 000024 AF 2 1280: IP (tos 0x8, ttl 64, id 48541, offset 0, flags
>>> [none], length: 1280) 10.128.6.1.22 > 10.128.1.6.53160: .
>>> 47548:48776(1228) ack 1330 win 33156 <nop,nop,timestamp 481770571
>>> 565002844>
>>> 011203 AF 2 52: IP (tos 0x8, ttl 64, id 60517, offset 0, flags
>>> [none], length: 52) 10.128.1.6.53160 > 10.128.6.1.22: . [tcp sum ok]
>>> 1330:1330(0) ack 41408 win 32542 <nop,nop,timestamp 565002855 481770530>
>>> 000058 AF 2 1280: IP (tos 0x8, ttl 64, id 15798, offset 0, flags
>>> [none], length: 1280) 10.128.6.1.22 > 10.128.1.6.53160: .
>>> 48776:50004(1228) ack 1330 win 33156 <nop,nop,timestamp 481770582
>>> 565002855>
>>> 000246 AF 2 1280: IP (tos 0x8, ttl 64, id 31721, offset 0, flags
>>> [none], length: 1280) 10.128.6.1.22 > 10.128.1.6.53160: .
>>> 50004:51232(1228) ack 1330 win 33156 <nop,nop,timestamp 481770583
>>> 565002855>
>>> 005147 AF 2 52: IP (tos 0x8, ttl 64, id 22347, offset 0, flags
>>> [none], length: 52) 10.128.1.6.53160 > 10.128.6.1.22: . [tcp sum ok]
>>> 1330:1330(0) ack 42636 win 33156 <nop,nop,timestamp 565002861 481770542>
>>> 000024 AF 2 1280: IP (tos 0x8, ttl 64, id 61057, offset 0, flags
>>> [none], length: 1280) 10.128.6.1.22 > 10.128.1.6.53160: .
>>> 51232:52460(1228) ack 1330 win 33156 <nop,nop,timestamp 481770588
>>> 565002861>
>>> 020769 AF 2 52: IP (tos 0x8, ttl 64, id 27692, offset 0, flags
>>> [none], length: 52) 10.128.1.6.53160 > 10.128.6.1.22: . [tcp sum ok]
>>> 1330:1330(0) ack 45092 win 32542 <nop,nop,timestamp 565002881 481770547>
>>> 000027 AF 2 1280: IP (tos 0x8, ttl 64, id 64167, offset 0, flags
>>> [none], length: 1280) 10.128.6.1.22 > 10.128.1.6.53160: .
>>> 52460:53688(1228) ack 1330 win 33156 <nop,nop,timestamp 481770609
>>> 565002881>
>>> 000209 AF 2 1280: IP (tos 0x8, ttl 64, id 45457, offset 0, flags
>>> [none], length: 1280) 10.128.6.1.22 > 10.128.1.6.53160: .
>>> 53688:54916(1228) ack 1330 win 33156 <nop,nop,timestamp 481770609
>>> 565002881>
>>> 005260 AF 2 52: IP (tos 0x8, ttl 64, id 53832, offset 0, flags
>>> [none], length: 52) 10.128.1.6.53160 > 10.128.6.1.22: . [tcp sum ok]
>>> 1330:1330(0) ack 46320 win 33156 <nop,nop,timestamp 565002887 481770567>
>>> 000024 AF 2 1280: IP (tos 0x8, ttl 64, id 3515, offset 0, flags
>>> [none], length: 1280) 10.128.6.1.22 > 10.128.1.6.53160: .
>>> 54916:56144(1228) ack 1330 win 33156 <nop,nop,timestamp 481770614
>>> 565002887>
>>> 011020 AF 2 52: IP (tos 0x8, ttl 64, id 11608, offset 0, flags
>>> [none], length: 52) 10.128.1.6.53160 > 10.128.6.1.22: . [tcp sum ok]
>>> 1330:1330(0) ack 48776 win 32542 <nop,nop,timestamp 565002898 481770568>
>>> 000026 AF 2 1280: IP (tos 0x8, ttl 64, id 5848, offset 0, flags
>>> [none], length: 1280) 10.128.6.1.22 > 10.128.1.6.53160: .
>>> 56144:57372(1228) ack 1330 win 33156 <nop,nop,timestamp 481770625
>>> 565002898>
>>> 000211 AF 2 1280: IP (tos 0x8, ttl 64, id 39892, offset 0, flags
>>> [none], length: 1280) 10.128.6.1.22 > 10.128.1.6.53160: .
>>> 57372:58600(1228) ack 1330 win 33156 <nop,nop,timestamp 481770625
>>> 565002898>
>>> 005641 AF 2 52: IP (tos 0x8, ttl 64, id 7943, offset 0, flags
>>> [none], length: 52) 10.128.1.6.53160 > 10.128.6.1.22: . [tcp sum ok]
>>> 1330:1330(0) ack 50004 win 33156 <nop,nop,timestamp 565002904 481770582>
>>> 000024 AF 2 1280: IP (tos 0x8, ttl 64, id 8678, offset 0, flags
>>> [none], length: 1280) 10.128.6.1.22 > 10.128.1.6.53160: .
>>> 58600:59828(1228) ack 1330 win 33156 <nop,nop,timestamp 481770631
>>> 565002904>
>>> 011072 AF 2 52: IP (tos 0x8, ttl 64, id 38257, offset 0, flags
>>> [none], length: 52) 10.128.1.6.53160 > 10.128.6.1.22: . [tcp sum ok]
>>> 1330:1330(0) ack 52460 win 32542 <nop,nop,timestamp 565002915 481770583>
>>> 000025 AF 2 1280: IP (tos 0x8, ttl 64, id 12255, offset 0, flags
>>> [none], length: 1280) 10.128.6.1.22 > 10.128.1.6.53160: .
>>> 59828:61056(1228) ack 1330 win 33156 <nop,nop,timestamp 481770642
>>> 565002915>
>>> 000209 AF 2 1280: IP (tos 0x8, ttl 64, id 46257, offset 0, flags
>>> [none], length: 1280) 10.128.6.1.22 > 10.128.1.6.53160: .
>>> 61056:62284(1228) ack 1330 win 33156 <nop,nop,timestamp 481770642
>>> 565002915>
>>> 000222 AF 2 1280: IP (tos 0x8, ttl 64, id 4093, offset 0, flags
>>> [none], length: 1280) 10.128.6.1.22 > 10.128.1.6.53160: .
>>> 62284:63512(1228) ack 1330 win 33156 <nop,nop,timestamp 481770643
>>> 565002915>
>>> 007065 AF 2 52: IP (tos 0x8, ttl 64, id 18720, offset 0, flags
>>> [none], length: 52) 10.128.1.6.53160 > 10.128.6.1.22: . [tcp sum ok]
>>> 1330:1330(0) ack 53688 win 33156 <nop,nop,timestamp 565002922 481770609>
>>> 000025 AF 2 1280: IP (tos 0x8, ttl 64, id 38378, offset 0, flags
>>> [none], length: 1280) 10.128.6.1.22 > 10.128.1.6.53160: .
>>> 63512:64740(1228) ack 1330 win 33156 <nop,nop,timestamp 481770650
>>> 565002922>
>>> 011034 AF 2 52: IP (tos 0x8, ttl 64, id 18718, offset 0, flags
>>> [none], length: 52) 10.128.1.6.53160 > 10.128.6.1.22: . [tcp sum ok]
>>> 1330:1330(0) ack 56144 win 32542 <nop,nop,timestamp 565002934 481770609>
>>> 000024 AF 2 1280: IP (tos 0x8, ttl 64, id 8148, offset 0, flags
>>> [none], length: 1280) 10.128.6.1.22 > 10.128.1.6.53160: .
>>> 64740:65968(1228) ack 1330 win 33156 <nop,nop,timestamp 481770661
>>> 565002934>
>>> 005991 AF 2 52: IP (tos 0x8, ttl 64, id 62285, offset 0, flags
>>> [none], length: 52) 10.128.1.6.53160 > 10.128.6.1.22: . [tcp sum ok]
>>> 1330:1330(0) ack 57372 win 33156 <nop,nop,timestamp 565002939 481770625>
>>> 010726 AF 2 52: IP (tos 0x8, ttl 64, id 1549, offset 0, flags
>>> [none], length: 52) 10.128.1.6.53160 > 10.128.6.1.22: . [tcp sum ok]
>>> 1330:1330(0) ack 59828 win 32542 <nop,nop,timestamp 565002950 481770625>
>>> 005670 AF 2 52: IP (tos 0x8, ttl 64, id 61504, offset 0, flags
>>> [none], length: 52) 10.128.1.6.53160 > 10.128.6.1.22: . [tcp sum ok]
>>> 1330:1330(0) ack 61056 win 33156 <nop,nop,timestamp 565002956 481770642>
>>> 011260 AF 2 52: IP (tos 0x8, ttl 64, id 32633, offset 0, flags
>>> [none], length: 52) 10.128.1.6.53160 > 10.128.6.1.22: . [tcp sum ok]
>>> 1330:1330(0) ack 63512 win 32542 <nop,nop,timestamp 565002967 481770642>
>>> 005510 AF 2 52: IP (tos 0x8, ttl 64, id 54614, offset 0, flags
>>> [none], length: 52) 10.128.1.6.53160 > 10.128.6.1.22: . [tcp sum ok]
>>> 1330:1330(0) ack 64740 win 33156 <nop,nop,timestamp 565002973 481770650>
>>> 104909 AF 2 52: IP (tos 0x8, ttl 64, id 50471, offset 0, flags
>>> [none], length: 52) 10.128.1.6.53160 > 10.128.6.1.22: . [tcp sum ok]
>>> 1330:1330(0) ack 65968 win 33156 <nop,nop,timestamp 565003078 481770661>
>>>
>>
>>
>> tcpdump -netttvvi ng0 host A.B.C.D:
>>
>>
>>> 000227 AF 2 1352: IP (tos 0x8, ttl 64, id 25895, offset 0, flags
>>> [none], length: 1352) E.F.G.H > A.B.C.D: ESP(spi=0x078b2968,seq=0x10b)
>>> 011042 AF 2 128: IP (tos 0x8, ttl 61, id 5786, offset 0, flags
>>> [none], length: 128) A.B.C.D > E.F.G.H: ESP(spi=0x0858046f,seq=0xf0)
>>> 000226 AF 2 1352: IP (tos 0x8, ttl 64, id 36701, offset 0, flags
>>> [none], length: 1352) E.F.G.H > A.B.C.D: ESP(spi=0x078b2968,seq=0x10c)
>>> 000216 AF 2 1352: IP (tos 0x8, ttl 64, id 8789, offset 0, flags
>>> [none], length: 1352) E.F.G.H > A.B.C.D: ESP(spi=0x078b2968,seq=0x10d)
>>> 004853 AF 2 128: IP (tos 0x8, ttl 61, id 17128, offset 0, flags
>>> [none], length: 128) A.B.C.D > E.F.G.H: ESP(spi=0x0858046f,seq=0xf1)
>>> 000227 AF 2 1352: IP (tos 0x8, ttl 64, id 34888, offset 0, flags
>>> [none], length: 1352) E.F.G.H > A.B.C.D: ESP(spi=0x078b2968,seq=0x10e)
>>> 018747 AF 2 128: IP (tos 0x8, ttl 61, id 14828, offset 0, flags
>>> [none], length: 128) A.B.C.D > E.F.G.H: ESP(spi=0x0858046f,seq=0xf2)
>>> 000248 AF 2 1352: IP (tos 0x8, ttl 64, id 34356, offset 0, flags
>>> [none], length: 1352) E.F.G.H > A.B.C.D: ESP(spi=0x078b2968,seq=0x10f)
>>> 000223 AF 2 1352: IP (tos 0x8, ttl 64, id 34151, offset 0, flags
>>> [none], length: 1352) E.F.G.H > A.B.C.D: ESP(spi=0x078b2968,seq=0x110)
>>> 005030 AF 2 128: IP (tos 0x8, ttl 61, id 45476, offset 0, flags
>>> [none], length: 128) A.B.C.D > E.F.G.H: ESP(spi=0x0858046f,seq=0xf3)
>>> 000228 AF 2 1352: IP (tos 0x8, ttl 64, id 39765, offset 0, flags
>>> [none], length: 1352) E.F.G.H > A.B.C.D: ESP(spi=0x078b2968,seq=0x111)
>>> 011247 AF 2 128: IP (tos 0x8, ttl 61, id 63692, offset 0, flags
>>> [none], length: 128) A.B.C.D > E.F.G.H: ESP(spi=0x0858046f,seq=0xf4)
>>> 000226 AF 2 1352: IP (tos 0x8, ttl 64, id 29240, offset 0, flags
>>> [none], length: 1352) E.F.G.H > A.B.C.D: ESP(spi=0x078b2968,seq=0x112)
>>> 000222 AF 2 1352: IP (tos 0x8, ttl 64, id 43306, offset 0, flags
>>> [none], length: 1352) E.F.G.H > A.B.C.D: ESP(spi=0x078b2968,seq=0x113)
>>> 005663 AF 2 128: IP (tos 0x8, ttl 61, id 32980, offset 0, flags
>>> [none], length: 128) A.B.C.D > E.F.G.H: ESP(spi=0x0858046f,seq=0xf5)
>>> 000228 AF 2 1352: IP (tos 0x8, ttl 64, id 56920, offset 0, flags
>>> [none], length: 1352) E.F.G.H > A.B.C.D: ESP(spi=0x078b2968,seq=0x114)
>>> 010190 AF 2 128: IP (tos 0x8, ttl 61, id 3206, offset 0, flags
>>> [none], length: 128) A.B.C.D > E.F.G.H: ESP(spi=0x0858046f,seq=0xf6)
>>> 000227 AF 2 1352: IP (tos 0x8, ttl 64, id 4655, offset 0, flags
>>> [none], length: 1352) E.F.G.H > A.B.C.D: ESP(spi=0x078b2968,seq=0x115)
>>> 000215 AF 2 1352: IP (tos 0x8, ttl 64, id 62740, offset 0, flags
>>> [none], length: 1352) E.F.G.H > A.B.C.D: ESP(spi=0x078b2968,seq=0x116)
>>> 000203 AF 2 1352: IP (tos 0x8, ttl 64, id 35642, offset 0, flags
>>> [none], length: 1352) E.F.G.H > A.B.C.D: ESP(spi=0x078b2968,seq=0x117)
>>> 006875 AF 2 128: IP (tos 0x8, ttl 61, id 37801, offset 0, flags
>>> [none], length: 128) A.B.C.D > E.F.G.H: ESP(spi=0x0858046f,seq=0xf7)
>>> 000234 AF 2 1352: IP (tos 0x8, ttl 64, id 41803, offset 0, flags
>>> [none], length: 1352) E.F.G.H > A.B.C.D: ESP(spi=0x078b2968,seq=0x118)
>>> 010651 AF 2 128: IP (tos 0x8, ttl 61, id 54256, offset 0, flags
>>> [none], length: 128) A.B.C.D > E.F.G.H: ESP(spi=0x0858046f,seq=0xf8)
>>> 000235 AF 2 1352: IP (tos 0x8, ttl 64, id 30732, offset 0, flags
>>> [none], length: 1352) E.F.G.H > A.B.C.D: ESP(spi=0x078b2968,seq=0x119)
>>> 007913 AF 2 128: IP (tos 0x8, ttl 61, id 7647, offset 0, flags
>>> [none], length: 128) A.B.C.D > E.F.G.H: ESP(spi=0x0858046f,seq=0xf9)
>>> 011166 AF 2 128: IP (tos 0x8, ttl 61, id 58037, offset 0, flags
>>> [none], length: 128) A.B.C.D > E.F.G.H: ESP(spi=0x0858046f,seq=0xfa)
>>> 005483 AF 2 128: IP (tos 0x8, ttl 61, id 65275, offset 0, flags
>>> [none], length: 128) A.B.C.D > E.F.G.H: ESP(spi=0x0858046f,seq=0xfb)
>>> 011250 AF 2 128: IP (tos 0x8, ttl 61, id 47289, offset 0, flags
>>> [none], length: 128) A.B.C.D > E.F.G.H: ESP(spi=0x0858046f,seq=0xfc)
>>> 005505 AF 2 128: IP (tos 0x8, ttl 61, id 203, offset 0, flags
>>> [none], length: 128) A.B.C.D > E.F.G.H: ESP(spi=0x0858046f,seq=0xfd)
>>> 104747 AF 2 128: IP (tos 0x8, ttl 61, id 45263, offset 0, flags
>>> [none], length: 128) A.B.C.D > E.F.G.H: ESP(spi=0x0858046f,seq=0xfe)
>>> 8. 338674 AF 2 128: IP (tos 0x8, ttl 61, id 36351, offset 0, flags
>>> [none], length: 128) A.B.C.D > E.F.G.H: ESP(spi=0x0858046f,seq=0xff)
>>> 319992 AF 2 128: IP (tos 0x8, ttl 61, id 18085, offset 0, flags
>>> [none], length: 128) A.B.C.D > E.F.G.H: ESP(spi=0x0858046f,seq=0x100)
>>> 441837 AF 2 128: IP (tos 0x8, ttl 61, id 58323, offset 0, flags
>>> [none], length: 128) A.B.C.D > E.F.G.H: ESP(spi=0x0858046f,seq=0x101)
>>> 684077 AF 2 128: IP (tos 0x8, ttl 61, id 35487, offset 0, flags
>>> [none], length: 128) A.B.C.D > E.F.G.H: ESP(spi=0x0858046f,seq=0x102)
>>> 1. 167602 AF 2 128: IP (tos 0x8, ttl 61, id 34442, offset 0, flags
>>> [none], length: 128) A.B.C.D > E.F.G.H: ESP(spi=0x0858046f,seq=0x103)
>>> 2. 136032 AF 2 128: IP (tos 0x8, ttl 61, id 8345, offset 0, flags
>>> [none], length: 128) A.B.C.D > E.F.G.H: ESP(spi=0x0858046f,seq=0x104)
>>> 2. 984665 AF 2 128: IP (tos 0x8, ttl 61, id 35456, offset 0, flags
>>> [none], length: 128) A.B.C.D > E.F.G.H: ESP(spi=0x0858046f,seq=0x105)
>>>
>>
>>
>>
>>> From what I'm seeing host B just stops sending without any reason. At
>>
>> least I don't see any fragmented packets. The only thing I've seen is
>> some packets doesn't get ack'ed by the receiver.
>>
>> These packets never get ack'ed:
>> 46320:47548(1228)
>> 50004:51232(1228)
>> 53688:54916(1228)
>> 57372:58600(1228)
>> 61056:62284(1228)
>>
>> On host A I dumped the following:
>>
>> tcpdump -netttvvi gif6
>>
>>
>>> 1129985378.941282 AF 2 52: IP (tos 0x8, ttl 64, id 41637, offset 0,
>>> flags [none], length: 52) 10.128.1.6.59762 > 10.128.6.1.22: . [tcp
>>> sum ok] 1330:1330(0) ack 45092 win 32542 <nop,nop,timestamp 574090240
>>> 490857876>
>>> 1129985378.952628 AF 2 1280: IP (tos 0x8, ttl 64, id 14004, offset
>>> 0, flags [none], length: 1280) 10.128.6.1.22 > 10.128.1.6.59762: .
>>> 45092:46320(1228) ack 1330 win 33156 <nop,nop,timestamp 490857901
>>> 574090210>
>>> 1129985378.952657 AF 2 52: IP (tos 0x8, ttl 64, id 23243, offset 0,
>>> flags [none], length: 52) 10.128.1.6.59762 > 10.128.6.1.22: . [tcp
>>> sum ok] 1330:1330(0) ack 46320 win 33156 <nop,nop,timestamp 574090251
>>> 490857901>
>>> 1129985378.958250 AF 2 1280: IP (tos 0x8, ttl 64, id 4306, offset 0,
>>> flags [none], length: 1280) 10.128.6.1.22 > 10.128.1.6.59762: .
>>> 46320:47548(1228) ack 1330 win 33156 <nop,nop,timestamp 490857901
>>> 574090210>
>>> 1129985378.971118 AF 2 1280: IP (tos 0x8, ttl 64, id 33534, offset
>>> 0, flags [none], length: 1280) 10.128.6.1.22 > 10.128.1.6.59762: .
>>> 47548:48776(1228) ack 1330 win 33156 <nop,nop,timestamp 490857920
>>> 574090229>
>>> 1129985378.971137 AF 2 52: IP (tos 0x8, ttl 64, id 60095, offset 0,
>>> flags [none], length: 52) 10.128.1.6.59762 > 10.128.6.1.22: . [tcp
>>> sum ok] 1330:1330(0) ack 48776 win 32542 <nop,nop,timestamp 574090270
>>> 490857901>
>>> 1129985378.982488 AF 2 1280: IP (tos 0x8, ttl 64, id 11459, offset
>>> 0, flags [none], length: 1280) 10.128.6.1.22 > 10.128.1.6.59762: .
>>> 48776:50004(1228) ack 1330 win 33156 <nop,nop,timestamp 490857931
>>> 574090240>
>>> 1129985378.982516 AF 2 52: IP (tos 0x8, ttl 64, id 33184, offset 0,
>>> flags [none], length: 52) 10.128.1.6.59762 > 10.128.6.1.22: . [tcp
>>> sum ok] 1330:1330(0) ack 50004 win 33156 <nop,nop,timestamp 574090281
>>> 490857931>
>>> 1129985378.987989 AF 2 1280: IP (tos 0x8, ttl 64, id 54180, offset
>>> 0, flags [none], length: 1280) 10.128.6.1.22 > 10.128.1.6.59762: .
>>> 50004:51232(1228) ack 1330 win 33156 <nop,nop,timestamp 490857931
>>> 574090240>
>>> 1129985378.994231 AF 2 1280: IP (tos 0x8, ttl 64, id 24535, offset
>>> 0, flags [none], length: 1280) 10.128.6.1.22 > 10.128.1.6.59762: .
>>> 51232:52460(1228) ack 1330 win 33156 <nop,nop,timestamp 490857942
>>> 574090251>
>>> 1129985378.994250 AF 2 52: IP (tos 0x8, ttl 64, id 30647, offset 0,
>>> flags [none], length: 52) 10.128.1.6.59762 > 10.128.6.1.22: . [tcp
>>> sum ok] 1330:1330(0) ack 52460 win 32542 <nop,nop,timestamp 574090293
>>> 490857931>
>>> 1129985379.012101 AF 2 1280: IP (tos 0x8, ttl 64, id 61397, offset
>>> 0, flags [none], length: 1280) 10.128.6.1.22 > 10.128.1.6.59762: .
>>> 52460:53688(1228) ack 1330 win 33156 <nop,nop,timestamp 490857960
>>> 574090270>
>>> 1129985379.012132 AF 2 52: IP (tos 0x8, ttl 64, id 60550, offset 0,
>>> flags [none], length: 52) 10.128.1.6.59762 > 10.128.6.1.22: . [tcp
>>> sum ok] 1330:1330(0) ack 53688 win 33156 <nop,nop,timestamp 574090311
>>> 490857960>
>>> 1129985379.017754 AF 2 1280: IP (tos 0x8, ttl 64, id 28408, offset
>>> 0, flags [none], length: 1280) 10.128.6.1.22 > 10.128.1.6.59762: .
>>> 53688:54916(1228) ack 1330 win 33156 <nop,nop,timestamp 490857961
>>> 574090270>
>>> 1129985379.023720 AF 2 1280: IP (tos 0x8, ttl 64, id 27558, offset
>>> 0, flags [none], length: 1280) 10.128.6.1.22 > 10.128.1.6.59762: .
>>> 54916:56144(1228) ack 1330 win 33156 <nop,nop,timestamp 490857972
>>> 574090281>
>>> 1129985379.023741 AF 2 52: IP (tos 0x8, ttl 64, id 21502, offset 0,
>>> flags [none], length: 52) 10.128.1.6.59762 > 10.128.6.1.22: . [tcp
>>> sum ok] 1330:1330(0) ack 56144 win 32542 <nop,nop,timestamp 574090322
>>> 490857961>
>>> 1129985379.035333 AF 2 1280: IP (tos 0x8, ttl 64, id 18885, offset
>>> 0, flags [none], length: 1280) 10.128.6.1.22 > 10.128.1.6.59762: .
>>> 56144:57372(1228) ack 1330 win 33156 <nop,nop,timestamp 490857984
>>> 574090293>
>>> 1129985379.035362 AF 2 52: IP (tos 0x8, ttl 64, id 59875, offset 0,
>>> flags [none], length: 52) 10.128.1.6.59762 > 10.128.6.1.22: . [tcp
>>> sum ok] 1330:1330(0) ack 57372 win 33156 <nop,nop,timestamp 574090334
>>> 490857984>
>>> 1129985379.040830 AF 2 1280: IP (tos 0x8, ttl 64, id 37252, offset
>>> 0, flags [none], length: 1280) 10.128.6.1.22 > 10.128.1.6.59762: .
>>> 57372:58600(1228) ack 1330 win 33156 <nop,nop,timestamp 490857984
>>> 574090293>
>>> 1129985379.046576 AF 2 1280: IP (tos 0x8, ttl 64, id 18349, offset
>>> 0, flags [none], length: 1280) 10.128.6.1.22 > 10.128.1.6.59762: .
>>> 58600:59828(1228) ack 1330 win 33156 <nop,nop,timestamp 490857984
>>> 574090293>
>>> 1129985379.046595 AF 2 52: IP (tos 0x8, ttl 64, id 43697, offset 0,
>>> flags [none], length: 52) 10.128.1.6.59762 > 10.128.6.1.22: . [tcp
>>> sum ok] 1330:1330(0) ack 59828 win 32542 <nop,nop,timestamp 574090345
>>> 490857984>
>>> 1129985379.064961 AF 2 1280: IP (tos 0x8, ttl 64, id 38300, offset
>>> 0, flags [none], length: 1280) 10.128.6.1.22 > 10.128.1.6.59762: .
>>> 59828:61056(1228) ack 1330 win 33156 <nop,nop,timestamp 490858013
>>> 574090322>
>>> 1129985379.064993 AF 2 52: IP (tos 0x8, ttl 64, id 47539, offset 0,
>>> flags [none], length: 52) 10.128.1.6.59762 > 10.128.6.1.22: . [tcp
>>> sum ok] 1330:1330(0) ack 61056 win 33156 <nop,nop,timestamp 574090364
>>> 490858013>
>>> 1129985379.070688 AF 2 1280: IP (tos 0x8, ttl 64, id 30345, offset
>>> 0, flags [none], length: 1280) 10.128.6.1.22 > 10.128.1.6.59762: .
>>> 61056:62284(1228) ack 1330 win 33156 <nop,nop,timestamp 490858013
>>> 574090322>
>>> 1129985379.076184 AF 2 1280: IP (tos 0x8, ttl 64, id 37536, offset
>>> 0, flags [none], length: 1280) 10.128.6.1.22 > 10.128.1.6.59762: .
>>> 62284:63512(1228) ack 1330 win 33156 <nop,nop,timestamp 490858014
>>> 574090322>
>>> 1129985379.076202 AF 2 52: IP (tos 0x8, ttl 64, id 34201, offset 0,
>>> flags [none], length: 52) 10.128.1.6.59762 > 10.128.6.1.22: . [tcp
>>> sum ok] 1330:1330(0) ack 63512 win 32542 <nop,nop,timestamp 574090375
>>> 490858013>
>>> 1129985379.081680 AF 2 1280: IP (tos 0x8, ttl 64, id 20637, offset
>>> 0, flags [none], length: 1280) 10.128.6.1.22 > 10.128.1.6.59762: .
>>> 63512:64740(1228) ack 1330 win 33156 <nop,nop,timestamp 490858025
>>> 574090334>
>>> 1129985379.081709 AF 2 52: IP (tos 0x8, ttl 64, id 59866, offset 0,
>>> flags [none], length: 52) 10.128.1.6.59762 > 10.128.6.1.22: . [tcp
>>> sum ok] 1330:1330(0) ack 64740 win 33156 <nop,nop,timestamp 574090380
>>> 490858025>
>>> 1129985379.087678 AF 2 1280: IP (tos 0x8, ttl 64, id 35213, offset
>>> 0, flags [none], length: 1280) 10.128.6.1.22 > 10.128.1.6.59762: .
>>> 64740:65968(1228) ack 1330 win 33156 <nop,nop,timestamp 490858036
>>> 574090345>
>>> 1129985379.186906 AF 2 52: IP (tos 0x8, ttl 64, id 2465, offset 0,
>>> flags [none], length: 52) 10.128.1.6.59762 > 10.128.6.1.22: . [tcp
>>> sum ok] 1330:1330(0) ack 65968 win 33156 <nop,nop,timestamp 574090486
>>> 490858036>
>>>
>>
>>
>> tcpdump -netttvvi em1 host E.F.G.H
>>
>>
>>> 1129985379.064825 00:13:c4:fa:6c:20 > 00:c0:9f:46:ec:c7, ethertype
>>> IPv4 (0x0800), length 1366: IP (tos 0x8, ttl 61, id 45003, offset 0,
>>> flags [none], length: 1352) E.F.G.H > A.B.C.D:
>>> ESP(spi=0x0e0dffaa,seq=0x3e)
>>> 1129985379.065024 00:c0:9f:46:ec:c7 > 00:13:c4:fa:6c:20, ethertype
>>> IPv4 (0x0800), length 142: IP (tos 0x8, ttl 64, id 1195, offset 0,
>>> flags [none], length: 128) A.B.C.D > E.F.G.H:
>>> ESP(spi=0x029a41b4,seq=0x2f)
>>> 1129985379.070572 00:13:c4:fa:6c:20 > 00:c0:9f:46:ec:c7, ethertype
>>> IPv4 (0x0800), length 1366: IP (tos 0x8, ttl 61, id 36820, offset 0,
>>> flags [none], length: 1352) E.F.G.H > A.B.C.D:
>>> ESP(spi=0x0e0dffaa,seq=0x3f)
>>> 1129985379.076069 00:13:c4:fa:6c:20 > 00:c0:9f:46:ec:c7, ethertype
>>> IPv4 (0x0800), length 1366: IP (tos 0x8, ttl 61, id 44971, offset 0,
>>> flags [none], length: 1352) E.F.G.H > A.B.C.D:
>>> ESP(spi=0x0e0dffaa,seq=0x40)
>>> 1129985379.076233 00:c0:9f:46:ec:c7 > 00:13:c4:fa:6c:20, ethertype
>>> IPv4 (0x0800), length 142: IP (tos 0x8, ttl 64, id 56964, offset 0,
>>> flags [none], length: 128) A.B.C.D > E.F.G.H:
>>> ESP(spi=0x029a41b4,seq=0x30)
>>> 1129985379.081565 00:13:c4:fa:6c:20 > 00:c0:9f:46:ec:c7, ethertype
>>> IPv4 (0x0800), length 1366: IP (tos 0x8, ttl 61, id 24742, offset 0,
>>> flags [none], length: 1352) E.F.G.H > A.B.C.D:
>>> ESP(spi=0x0e0dffaa,seq=0x41)
>>> 1129985379.081741 00:c0:9f:46:ec:c7 > 00:13:c4:fa:6c:20, ethertype
>>> IPv4 (0x0800), length 142: IP (tos 0x8, ttl 64, id 9390, offset 0,
>>> flags [none], length: 128) A.B.C.D > E.F.G.H:
>>> ESP(spi=0x029a41b4,seq=0x31)
>>> 1129985379.087562 00:13:c4:fa:6c:20 > 00:c0:9f:46:ec:c7, ethertype
>>> IPv4 (0x0800), length 1366: IP (tos 0x8, ttl 61, id 48065, offset 0,
>>> flags [none], length: 1352) E.F.G.H > A.B.C.D:
>>> ESP(spi=0x0e0dffaa,seq=0x42)
>>> 1129985379.186945 00:c0:9f:46:ec:c7 > 00:13:c4:fa:6c:20, ethertype
>>> IPv4 (0x0800), length 142: IP (tos 0x8, ttl 64, id 36315, offset 0,
>>> flags [none], length: 128) A.B.C.D > E.F.G.H:
>>> ESP(spi=0x029a41b4,seq=0x32)
>>>
>>
>>
>> If I'm not misleaded, this also doesn't show any errors except the
>> missing ack's. host B just stops sending. If there's an ack missing,
>> doesn't have the sending host to just repeat the un-ack'ed packet?
>>
>> The IPSec tunnel does not die. Even shortly after the (scp) transfer
>> stalls the tunnel itself is still usable (for small amounts of data). To
>> make it more worse, when disabling pf at the senders side, the transfer
>> works. I've tripple checked pflog for denied packets on both sides but
>> pf didn't filter any packets out.
>>
>> When disabling the IPSec rules using `setkey -F; setkey -FP' on the
>> tunnel for a moment, the scp transfer does not stall. So it's not a gif
>> issue.
>>
>> It doesn't seem to be an MTU issue (pf has also the rule 'scrub in/out
>> all no-df'), but what kind of issue is that?? Has anybody ever
>> experienced similar things? Or am I misinterpreting the tcpdump output?
>>
>>
>> Any help and hint is appreciated! Without an error message I'm lost.
>>
>> Volker
>>
>> _______________________________________________
>> freebsd-net at freebsd.org mailing list
>> http://lists.freebsd.org/mailman/listinfo/freebsd-net
>> To unsubscribe, send any mail to "freebsd-net-unsubscribe at freebsd.org"
>>
>>
>
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