Re: Excessive TCP retransmits over lossless, high latency link

Jamie Lokier
2001-09-01T20:17:57Z

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kuznet@ms2.inr.ac.ru wrote:
> > binary trace with "tcpdump -n -w" is attached,
>
> I am afraid you forgot it.

I have attached various files to this message. Hopefully the names make
it clear which they are.

> > I am wondering if not sending so many duplicate ACKs would help the
> > broken sender (I know, that is against RFC793 but hey if it works...).
> If it works, hack kernel not to send dupacks. What is the problem? :-)

I hate rebooting :-)

> Yes, on such links fast retransmit is not useful in any case.

Should I turn of /proc/sys/net/ipv4/tcp_fack then?

> Actually, you can make something from your side: if rtt is so high,
> most likely this means excessive queueing.

Yes, definitely. Btw, I saw a ping round trip time of 162s just now.

> You can fight this
> advertising smaller window (f.e. adding option "window N" to route).
> If intepacket gap is 5sec and rtt 23, you can divide window by 23/5
> and rtt should drop to some more reasonable number. "Theoretical"
> bandwidth will reduce, but practical will grow.
>
>
> > For the sake of a Linux test, I shall try proxying this stream via a
> > Linux 2.4.2 box I have on the net, and see if it is an improvement.
>
> Yes, it is intersting.

I've tried it, with no special settings (mtu or window or sack etc.) at
either end. Local end is Linux 2.4.7, remote is 2.4.2-2 from Red Hat 7.1.
The remote is proxying a connection to the final mailserver.

I saw very few retransmits in a single message download. SACK appears
occasionally. I don't really understand the local reaction to SACK, or
why a SACK option appears in one ACK sent locally and not the following
ACK, even though the SACK mentions data that does not arrive between the
two locally sent ACKs.

The throughput difference was obvious: POP3 negotiation + 30k message +
headers took:

5 min 31 sec downloading unknown OS -> Linux 2.4.7
2 min 15 sec downloading Linux 2.4.2 -> Linux 2.4.7

Looking at the traces, I expect the improvement on the straight data
part is better than 2:1, because I saw so many retransmits with the
other OS and hardly any with Linux as the server.

If someone would like to do an OS type probe on sdps.demon.co.uk, we
will know which OS should be avoided for this kind of connection ;-)

It is still very slow considering it is advertised as "9600 baud" though
:-(

cheers,
-- Jamie

[-- Attachment #2: pktlog-from-notlinux --]
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[-- Attachment #3: pktlog-from-notlinux.txt --]
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19:43:06.892991 > 193.237.65.219.32855 > 158.152.1.58.domain: 48716+ A? sdps.demon.co.uk. (34) (DF)
19:43:08.952861 < 158.152.1.58.domain > 193.237.65.219.32855: 48716 5/4/4 CNAME pop3.mail.demon.net., A 194.217.242.59, A 194.217.242.22, (266)
19:43:08.989850 > 193.237.65.219.32855 > 158.152.1.58.domain: 48717+ AAAA? sdps.demon.co.uk. (34) (DF)
19:43:10.525449 < 158.152.1.58.domain > 193.237.65.219.32855: 48717 1/1/0 CNAME pop3.mail.demon.net. (114)
19:43:10.526084 > 193.237.65.219.32855 > 158.152.1.58.domain: 48718+ A? sdps.demon.co.uk. (34) (DF)
19:43:12.572859 < 158.152.1.58.domain > 193.237.65.219.32855: 48718 5/4/4 CNAME pop3.mail.demon.net., A 194.217.242.59, A 194.217.242.22, (266)
19:43:12.573433 > 193.237.65.219.32809 > 194.217.242.59.pop3: S 2296392844:2296392844(0) win 5840 <mss 1460,sackOK,timestamp 1404252 0,nop,wscale 0> (DF)
19:43:13.615650 < 194.217.242.59.pop3 > 193.237.65.219.32809: S 2152317245:2152317245(0) ack 2296392845 win 8760 <mss 1460> (DF)
19:43:13.615773 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 1:1(0) ack 1 win 5840 (DF)
19:43:14.632866 < 194.217.242.59.pop3 > 193.237.65.219.32809: P 1:44(43) ack 1 win 8760 (DF)
19:43:14.632961 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 1:1(0) ack 44 win 5840 (DF)
19:43:14.649264 > 193.237.65.219.32809 > 194.217.242.59.pop3: P 1:25(24) ack 44 win 5840 (DF)
19:43:15.672850 < 194.217.242.59.pop3 > 193.237.65.219.32809: P 44:50(6) ack 25 win 8760 (DF)
19:43:15.685004 > 193.237.65.219.32809 > 194.217.242.59.pop3: P 25:40(15) ack 50 win 5840 (DF)
19:43:16.702917 < 194.217.242.59.pop3 > 193.237.65.219.32809: . 50:50(0) ack 40 win 8760 (DF)
19:43:17.203063 < 194.217.242.59.pop3 > 193.237.65.219.32809: P 50:56(6) ack 40 win 8760 (DF)
19:43:17.242650 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 40:40(0) ack 56 win 5840 (DF)
19:43:20.222880 > 193.237.65.219.32809 > 194.217.242.59.pop3: P 40:46(6) ack 56 win 5840 (DF)
19:43:21.233068 < 194.217.242.59.pop3 > 193.237.65.219.32809: P 56:69(13) ack 46 win 8760 (DF)
19:43:21.233354 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 46:46(0) ack 69 win 5840 (DF)
19:43:21.251867 > 193.237.65.219.32809 > 194.217.242.59.pop3: P 46:52(6) ack 69 win 5840 (DF)
19:43:22.272869 < 194.217.242.59.pop3 > 193.237.65.219.32809: P 69:124(55) ack 52 win 8760 (DF)
19:43:22.308400 > 193.237.65.219.32809 > 194.217.242.59.pop3: P 52:58(6) ack 124 win 5840 (DF)
19:43:23.322929 < 194.217.242.59.pop3 > 193.237.65.219.32809: P 124:151(27) ack 58 win 8760 (DF)
19:43:23.349075 > 193.237.65.219.32809 > 194.217.242.59.pop3: P 58:74(16) ack 151 win 5840 (DF)
19:43:27.102700 > 193.237.65.219.32809 > 194.217.242.59.pop3: P 58:74(16) ack 151 win 5840 (DF)
19:43:29.732891 < 194.217.242.59.pop3 > 193.237.65.219.32809: P 151:1611(1460) ack 74 win 8760 (DF)
19:43:29.733159 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 74:74(0) ack 1611 win 8760 (DF)
19:43:34.982965 < 194.217.242.59.pop3 > 193.237.65.219.32809: P 1611:3071(1460) ack 74 win 8760 (DF)
19:43:35.022675 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 74:74(0) ack 3071 win 11680 (DF)
19:43:40.262962 < 194.217.242.59.pop3 > 193.237.65.219.32809: P 3071:4531(1460) ack 74 win 8760 (DF)
19:43:40.263062 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 74:74(0) ack 4531 win 14600 (DF)
19:43:45.512900 < 194.217.242.59.pop3 > 193.237.65.219.32809: P 4531:5991(1460) ack 74 win 8760 (DF)
19:43:45.512991 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 74:74(0) ack 5991 win 17520 (DF)
19:43:45.512905 < 194.217.242.59.pop3 > 193.237.65.219.32809: . 5991:5991(0) ack 74 win 8760 (DF)
19:43:50.752866 < 194.217.242.59.pop3 > 193.237.65.219.32809: . 151:1611(1460) ack 74 win 8760 (DF)
19:43:50.752954 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 74:74(0) ack 5991 win 17520 (DF)
19:43:55.952900 < 194.217.242.59.pop3 > 193.237.65.219.32809: . 1611:3071(1460) ack 74 win 8760 (DF)
19:43:55.952987 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 74:74(0) ack 5991 win 17520 (DF)
19:44:01.162979 < 194.217.242.59.pop3 > 193.237.65.219.32809: . 3071:4531(1460) ack 74 win 8760 (DF)
19:44:01.163072 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 74:74(0) ack 5991 win 17520 (DF)
19:44:06.382817 < 194.217.242.59.pop3 > 193.237.65.219.32809: P 5991:7451(1460) ack 74 win 8760 (DF)
19:44:06.382909 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 74:74(0) ack 7451 win 20440 (DF)
19:44:11.602458 < 194.217.242.59.pop3 > 193.237.65.219.32809: . 3071:4531(1460) ack 74 win 8760 (DF)
19:44:11.602546 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 74:74(0) ack 7451 win 20440 (DF)
19:44:16.812904 < 194.217.242.59.pop3 > 193.237.65.219.32809: . 4531:5991(1460) ack 74 win 8760 (DF)
19:44:16.812990 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 74:74(0) ack 7451 win 20440 (DF)
19:44:22.002981 < 194.217.242.59.pop3 > 193.237.65.219.32809: . 5991:7451(1460) ack 74 win 8760 (DF)
19:44:22.003076 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 74:74(0) ack 7451 win 20440 (DF)
19:44:25.642892 < 194.217.242.59.pop3 > 193.237.65.219.32809: P 7451:8342(891) ack 74 win 8760 (DF)
19:44:25.642985 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 74:74(0) ack 8342 win 23360 (DF)
19:44:30.852962 < 194.217.242.59.pop3 > 193.237.65.219.32809: . 5991:7451(1460) ack 74 win 8760 (DF)
19:44:30.853052 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 74:74(0) ack 8342 win 23360 (DF)
19:44:36.062951 < 194.217.242.59.pop3 > 193.237.65.219.32809: . 5991:7451(1460) ack 74 win 8760 (DF)
19:44:36.063046 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 74:74(0) ack 8342 win 23360 (DF)
19:44:41.282732 < 194.217.242.59.pop3 > 193.237.65.219.32809: . 5991:7451(1460) ack 74 win 8760 (DF)
19:44:41.282825 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 74:74(0) ack 8342 win 23360 (DF)
19:44:44.402896 < 194.217.242.59.pop3 > 193.237.65.219.32809: . 7451:8342(891) ack 74 win 8760 (DF)
19:44:44.402995 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 74:74(0) ack 8342 win 23360 (DF)
19:44:49.612909 < 194.217.242.59.pop3 > 193.237.65.219.32809: . 8342:9802(1460) ack 74 win 8760 (DF)
19:44:49.612996 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 74:74(0) ack 9802 win 26280 (DF)
19:44:54.832979 < 194.217.242.59.pop3 > 193.237.65.219.32809: . 9802:11262(1460) ack 74 win 8760 (DF)
19:44:54.833070 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 74:74(0) ack 11262 win 29200 (DF)
19:45:00.052742 < 194.217.242.59.pop3 > 193.237.65.219.32809: . 7451:8911(1460) ack 74 win 8760 (DF)
19:45:00.052831 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 74:74(0) ack 11262 win 29200 (DF)
19:45:05.262884 < 194.217.242.59.pop3 > 193.237.65.219.32809: . 7451:8911(1460) ack 74 win 8760 (DF)
19:45:05.262978 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 74:74(0) ack 11262 win 29200 (DF)
19:45:10.482889 < 194.217.242.59.pop3 > 193.237.65.219.32809: . 8342:9802(1460) ack 74 win 8760 (DF)
19:45:10.482979 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 74:74(0) ack 11262 win 29200 (DF)
19:45:15.702883 < 194.217.242.59.pop3 > 193.237.65.219.32809: . 11262:12722(1460) ack 74 win 8760 (DF)
19:45:15.702975 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 74:74(0) ack 12722 win 32120 (DF)
19:45:20.922616 < 194.217.242.59.pop3 > 193.237.65.219.32809: . 8342:9802(1460) ack 74 win 8760 (DF)
19:45:20.922706 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 74:74(0) ack 12722 win 32120 (DF)
19:45:26.132863 < 194.217.242.59.pop3 > 193.237.65.219.32809: . 8342:9802(1460) ack 74 win 8760 (DF)
19:45:26.132958 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 74:74(0) ack 12722 win 32120 (DF)
19:45:31.352814 < 194.217.242.59.pop3 > 193.237.65.219.32809: . 9802:11262(1460) ack 74 win 8760 (DF)
19:45:31.352898 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 74:74(0) ack 12722 win 32120 (DF)
19:45:36.572622 < 194.217.242.59.pop3 > 193.237.65.219.32809: . 12722:14182(1460) ack 74 win 8760 (DF)
19:45:36.572709 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 74:74(0) ack 14182 win 35040 (DF)
19:45:41.772897 < 194.217.242.59.pop3 > 193.237.65.219.32809: P 14182:15642(1460) ack 74 win 8760 (DF)
19:45:41.772985 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 74:74(0) ack 15642 win 37960 (DF)
19:45:46.982994 < 194.217.242.59.pop3 > 193.237.65.219.32809: . 11262:12722(1460) ack 74 win 8760 (DF)
19:45:46.983083 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 74:74(0) ack 15642 win 37960 (DF)
19:45:50.102890 < 194.217.242.59.pop3 > 193.237.65.219.32809: . 15642:16533(891) ack 74 win 8760 (DF)
19:45:50.102989 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 74:74(0) ack 16533 win 37960 (DF)
19:45:55.328662 < 194.217.242.59.pop3 > 193.237.65.219.32809: . 11262:12722(1460) ack 74 win 8760 (DF)
19:45:55.328755 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 74:74(0) ack 16533 win 37960 (DF)
19:46:00.534606 < 194.217.242.59.pop3 > 193.237.65.219.32809: . 12722:14182(1460) ack 74 win 8760 (DF)
19:46:00.534691 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 74:74(0) ack 16533 win 37960 (DF)
19:46:05.777455 < 194.217.242.59.pop3 > 193.237.65.219.32809: . 16533:17993(1460) ack 74 win 8760 (DF)
19:46:05.777543 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 74:74(0) ack 17993 win 40880 (DF)
19:46:11.002902 < 194.217.242.59.pop3 > 193.237.65.219.32809: . 17993:19453(1460) ack 74 win 8760 (DF)
19:46:11.002992 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 74:74(0) ack 19453 win 43800 (DF)
19:46:16.252870 < 194.217.242.59.pop3 > 193.237.65.219.32809: . 12722:14182(1460) ack 74 win 8760 (DF)
19:46:16.252965 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 74:74(0) ack 19453 win 43800 (DF)
19:46:21.482878 < 194.217.242.59.pop3 > 193.237.65.219.32809: . 12722:14182(1460) ack 74 win 8760 (DF)
19:46:21.482967 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 74:74(0) ack 19453 win 43800 (DF)
19:46:26.732886 < 194.217.242.59.pop3 > 193.237.65.219.32809: . 14182:15642(1460) ack 74 win 8760 (DF)
19:46:26.732977 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 74:74(0) ack 19453 win 43800 (DF)
19:46:31.982906 < 194.217.242.59.pop3 > 193.237.65.219.32809: . 15642:17102(1460) ack 74 win 8760 (DF)
19:46:31.982992 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 74:74(0) ack 19453 win 43800 (DF)
19:46:37.234530 < 194.217.242.59.pop3 > 193.237.65.219.32809: . 16533:17993(1460) ack 74 win 8760 (DF)
19:46:37.234617 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 74:74(0) ack 19453 win 43800 (DF)
19:46:42.472760 < 194.217.242.59.pop3 > 193.237.65.219.32809: . 17993:19453(1460) ack 74 win 8760 (DF)
19:46:42.472856 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 74:74(0) ack 19453 win 43800 (DF)
19:46:47.687936 < 194.217.242.59.pop3 > 193.237.65.219.32809: . 19453:20913(1460) ack 74 win 8760 (DF)
19:46:47.688029 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 74:74(0) ack 20913 win 46720 (DF)
19:46:52.932888 < 194.217.242.59.pop3 > 193.237.65.219.32809: P 20913:22373(1460) ack 74 win 8760 (DF)
19:46:52.932976 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 74:74(0) ack 22373 win 49640 (DF)
19:46:58.172866 < 194.217.242.59.pop3 > 193.237.65.219.32809: . 19453:20913(1460) ack 74 win 8760 (DF)
19:46:58.172953 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 74:74(0) ack 22373 win 49640 (DF)
19:47:03.402904 < 194.217.242.59.pop3 > 193.237.65.219.32809: P 22373:23833(1460) ack 74 win 8760 (DF)
19:47:03.402993 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 74:74(0) ack 23833 win 52560 (DF)
19:47:08.652863 < 194.217.242.59.pop3 > 193.237.65.219.32809: . 19453:20913(1460) ack 74 win 8760 (DF)
19:47:08.652952 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 74:74(0) ack 23833 win 52560 (DF)
19:47:14.414511 < 194.217.242.59.pop3 > 193.237.65.219.32809: . 19453:20913(1460) ack 74 win 8760 (DF)
19:47:14.414604 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 74:74(0) ack 23833 win 52560 (DF)
19:47:19.622913 < 194.217.242.59.pop3 > 193.237.65.219.32809: . 20913:22373(1460) ack 74 win 8760 (DF)
19:47:19.623003 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 74:74(0) ack 23833 win 52560 (DF)
19:47:23.282880 < 194.217.242.59.pop3 > 193.237.65.219.32809: P 23833:24725(892) ack 74 win 8760 (DF)
19:47:23.282980 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 74:74(0) ack 24725 win 52560 (DF)
19:47:28.522888 < 194.217.242.59.pop3 > 193.237.65.219.32809: . 22373:23833(1460) ack 74 win 8760 (DF)
19:47:28.522976 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 74:74(0) ack 24725 win 52560 (DF)
19:47:34.272886 < 194.217.242.59.pop3 > 193.237.65.219.32809: . 24725:26185(1460) ack 74 win 8760 (DF)
19:47:34.272981 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 74:74(0) ack 26185 win 55480 (DF)
19:47:40.002881 < 194.217.242.59.pop3 > 193.237.65.219.32809: . 23833:25293(1460) ack 74 win 8760 (DF)
19:47:40.002971 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 74:74(0) ack 26185 win 55480 (DF)
19:47:45.202902 < 194.217.242.59.pop3 > 193.237.65.219.32809: . 26185:27645(1460) ack 74 win 8760 (DF)
19:47:45.202998 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 74:74(0) ack 27645 win 58400 (DF)
19:47:50.394404 < 194.217.242.59.pop3 > 193.237.65.219.32809: . 27645:29105(1460) ack 74 win 8760 (DF)
19:47:50.394500 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 74:74(0) ack 29105 win 61320 (DF)
19:47:56.121837 < 194.217.242.59.pop3 > 193.237.65.219.32809: . 23833:25293(1460) ack 74 win 8760 (DF)
19:47:56.121944 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 74:74(0) ack 29105 win 61320 (DF)
19:48:01.302918 < 194.217.242.59.pop3 > 193.237.65.219.32809: . 24725:26185(1460) ack 74 win 8760 (DF)
19:48:01.303011 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 74:74(0) ack 29105 win 61320 (DF)
19:48:07.022900 < 194.217.242.59.pop3 > 193.237.65.219.32809: . 24725:26185(1460) ack 74 win 8760 (DF)
19:48:07.022992 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 74:74(0) ack 29105 win 61320 (DF)
19:48:12.212914 < 194.217.242.59.pop3 > 193.237.65.219.32809: . 26185:27645(1460) ack 74 win 8760 (DF)
19:48:12.213001 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 74:74(0) ack 29105 win 61320 (DF)
19:48:17.432888 < 194.217.242.59.pop3 > 193.237.65.219.32809: . 27645:29105(1460) ack 74 win 8760 (DF)
19:48:17.432985 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 74:74(0) ack 29105 win 61320 (DF)
19:48:22.642896 < 194.217.242.59.pop3 > 193.237.65.219.32809: . 29105:30565(1460) ack 74 win 8760 (DF)
19:48:22.642984 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 74:74(0) ack 30565 win 62780 (DF)
19:48:24.212871 < 194.217.242.59.pop3 > 193.237.65.219.32809: P 30565:31088(523) ack 74 win 8760 (DF)
19:48:24.212966 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 74:74(0) ack 31088 win 62780 (DF)
19:48:24.245885 > 193.237.65.219.32809 > 194.217.242.59.pop3: P 74:82(8) ack 31088 win 62780 (DF)
19:48:29.452732 < 194.217.242.59.pop3 > 193.237.65.219.32809: P 29105:30565(1460) ack 74 win 8760 (DF)
19:48:29.452827 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 82:82(0) ack 31088 win 62780 (DF)
19:48:31.762704 > 193.237.65.219.32809 > 194.217.242.59.pop3: P 74:82(8) ack 31088 win 62780 (DF)
19:48:34.882885 < 194.217.242.59.pop3 > 193.237.65.219.32809: P 29105:30565(1460) ack 74 win 8760 (DF)
19:48:34.882977 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 82:82(0) ack 31088 win 62780 (DF)
19:48:36.452866 < 194.217.242.59.pop3 > 193.237.65.219.32809: P 30565:31088(523) ack 74 win 8760 (DF)
19:48:36.452978 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 82:82(0) ack 31088 win 62780 (DF)
19:48:36.452873 < 194.217.242.59.pop3 > 193.237.65.219.32809: P 31088:31094(6) ack 82 win 8760 (DF)
19:48:36.453045 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 82:82(0) ack 31094 win 62780 (DF)
19:48:36.464298 > 193.237.65.219.32809 > 194.217.242.59.pop3: P 82:88(6) ack 31094 win 62780 (DF)
19:48:36.474321 < 194.217.242.59.pop3 > 193.237.65.219.32809: P 31088:31094(6) ack 82 win 8760 (DF)
19:48:36.474421 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 88:88(0) ack 31094 win 62780 (DF)
19:48:36.482923 < 194.217.242.59.pop3 > 193.237.65.219.32809: . 31094:31094(0) ack 82 win 8760 (DF)
19:48:36.502875 < 194.217.242.59.pop3 > 193.237.65.219.32809: P 31088:31094(6) ack 82 win 8760 (DF)
19:48:36.502936 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 88:88(0) ack 31094 win 62780 (DF)
19:48:36.502880 < 194.217.242.59.pop3 > 193.237.65.219.32809: P 31088:31094(6) ack 82 win 8760 (DF)
19:48:36.502992 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 88:88(0) ack 31094 win 62780 (DF)
19:48:37.546707 < 194.217.242.59.pop3 > 193.237.65.219.32809: P 31094:31100(6) ack 88 win 8760 (DF)
19:48:37.546812 > 193.237.65.219.32809 > 194.217.242.59.pop3: . 88:88(0) ack 31100 win 62780 (DF)
19:48:37.546714 < 194.217.242.59.pop3 > 193.237.65.219.32809: F 31100:31100(0) ack 88 win 8760 (DF)
19:48:37.556924 > 193.237.65.219.32809 > 194.217.242.59.pop3: F 88:88(0) ack 31101 win 62780 (DF)
19:48:38.571482 < 194.217.242.59.pop3 > 193.237.65.219.32809: . 31101:31101(0) ack 89 win 8760 (DF)

[-- Attachment #4: pktlog-from-linux242 --]
[-- Type: application/octet-stream, Size: 9909 bytes --]

[-- Attachment #5: pktlog-from-linux242.txt --]
[-- Type: text/plain, Size: 11047 bytes --]

20:49:10.535879 > 193.237.65.219.32857 > 158.152.1.58.domain: 4313+ A? sdps.demon.co.uk. (34) (DF)
20:49:12.607387 < 158.152.1.58.domain > 193.237.65.219.32857: 4313 5/4/4 CNAME pop3.mail.demon.net., A 194.217.242.58, A 194.217.242.59, (266)
20:49:13.112862 < 194.217.242.7.50453 > 193.237.65.219.smtp: S 3979673482:3979673482(0) win 8760 <mss 1460> (DF)
20:49:13.114345 > 193.237.65.219 > 194.217.242.7: icmp: 193.237.65.219 tcp port smtp unreachable [tos 0xc0]
20:49:13.666321 > 193.237.65.219.32833 > 217.33.12.64.4000: S 2192994338:2192994338(0) win 5840 <mss 1460,sackOK,timestamp 1800361 0,nop,wscale 0> (DF)
20:49:14.689811 < 217.33.12.64.4000 > 193.237.65.219.32833: S 1422559437:1422559437(0) ack 2192994339 win 5792 <mss 1460,sackOK,timestamp 18895656 1800361,nop,wscale 0> (DF)
20:49:14.689916 > 193.237.65.219.32833 > 217.33.12.64.4000: . 1:1(0) ack 1 win 5840 <nop,nop,timestamp 1800463 18895656> (DF)
20:49:15.722871 < 217.33.12.64.4000 > 193.237.65.219.32833: P 1:44(43) ack 1 win 5792 <nop,nop,timestamp 18895765 1800463> (DF)
20:49:15.722963 > 193.237.65.219.32833 > 217.33.12.64.4000: . 1:1(0) ack 44 win 5840 <nop,nop,timestamp 1800567 18895765> (DF)
20:49:15.759946 > 193.237.65.219.32833 > 217.33.12.64.4000: P 1:25(24) ack 44 win 5840 <nop,nop,timestamp 1800570 18895765> (DF)
20:49:16.792932 < 217.33.12.64.4000 > 193.237.65.219.32833: . 44:44(0) ack 25 win 5792 <nop,nop,timestamp 18895869 1800570> (DF)
20:49:16.792940 < 217.33.12.64.4000 > 193.237.65.219.32833: P 44:50(6) ack 25 win 5792 <nop,nop,timestamp 18895871 1800570> (DF)
20:49:16.813410 > 193.237.65.219.32833 > 217.33.12.64.4000: P 25:40(15) ack 50 win 5840 <nop,nop,timestamp 1800676 18895871> (DF)
20:49:17.832858 < 217.33.12.64.4000 > 193.237.65.219.32833: . 50:50(0) ack 40 win 5792 <nop,nop,timestamp 18895977 1800676> (DF)
20:49:18.342863 < 217.33.12.64.4000 > 193.237.65.219.32833: P 50:56(6) ack 40 win 5792 <nop,nop,timestamp 18895986 1800676> (DF)
20:49:18.382680 > 193.237.65.219.32833 > 217.33.12.64.4000: . 40:40(0) ack 56 win 5840 <nop,nop,timestamp 1800833 18895986> (DF)
20:49:21.377055 > 193.237.65.219.32833 > 217.33.12.64.4000: P 40:46(6) ack 56 win 5840 <nop,nop,timestamp 1801132 18895986> (DF)
20:49:22.902855 < 217.33.12.64.4000 > 193.237.65.219.32833: . 56:56(0) ack 46 win 5792 <nop,nop,timestamp 18896469 1801132> (DF)
20:49:23.412846 < 217.33.12.64.4000 > 193.237.65.219.32833: P 56:69(13) ack 46 win 5792 <nop,nop,timestamp 18896471 1801132> (DF)
20:49:23.412935 > 193.237.65.219.32833 > 217.33.12.64.4000: . 46:46(0) ack 69 win 5840 <nop,nop,timestamp 1801336 18896471> (DF)
20:49:23.433965 > 193.237.65.219.32833 > 217.33.12.64.4000: P 46:52(6) ack 69 win 5840 <nop,nop,timestamp 1801338 18896471> (DF)
20:49:24.462871 < 217.33.12.64.4000 > 193.237.65.219.32833: P 69:124(55) ack 52 win 5792 <nop,nop,timestamp 18896638 1801338> (DF)
20:49:24.511822 > 193.237.65.219.32833 > 217.33.12.64.4000: . 52:52(0) ack 124 win 5840 <nop,nop,timestamp 1801445 18896638> (DF)
20:49:24.517953 > 193.237.65.219.32833 > 217.33.12.64.4000: P 52:58(6) ack 124 win 5840 <nop,nop,timestamp 1801446 18896638> (DF)
20:49:25.532880 < 217.33.12.64.4000 > 193.237.65.219.32833: P 124:151(27) ack 58 win 5792 <nop,nop,timestamp 18896752 1801446> (DF)
20:49:25.532976 > 193.237.65.219.32833 > 217.33.12.64.4000: . 58:58(0) ack 151 win 5840 <nop,nop,timestamp 1801548 18896752> (DF)
20:49:25.581259 > 193.237.65.219.32833 > 217.33.12.64.4000: P 58:74(16) ack 151 win 5840 <nop,nop,timestamp 1801552 18896752> (DF)
20:49:26.605437 < 217.33.12.64.4000 > 193.237.65.219.32833: . 151:151(0) ack 74 win 5792 <nop,nop,timestamp 18896860 1801552> (DF)
20:49:32.302918 < 217.33.12.64.4000 > 193.237.65.219.32833: . 151:1599(1448) ack 74 win 5792 <nop,nop,timestamp 18896860 1801552> (DF)
20:49:32.303020 > 193.237.65.219.32833 > 217.33.12.64.4000: . 74:74(0) ack 1599 win 8688 <nop,nop,timestamp 1802225 18896860> (DF)
20:49:32.302923 < 217.33.12.64.4000 > 193.237.65.219.32833: P 1599:1611(12) ack 74 win 5792 <nop,nop,timestamp 18896860 1801552> (DF)
20:49:32.303081 > 193.237.65.219.32833 > 217.33.12.64.4000: . 74:74(0) ack 1611 win 8688 <nop,nop,timestamp 1802225 18896860> (DF)
20:49:39.072902 < 217.33.12.64.4000 > 193.237.65.219.32833: . 1611:3059(1448) ack 74 win 5792 <nop,nop,timestamp 18897529 1802225> (DF)
20:49:39.073002 > 193.237.65.219.32833 > 217.33.12.64.4000: . 74:74(0) ack 3059 win 11584 <nop,nop,timestamp 1802902 18897529> (DF)
20:49:44.319061 < 217.33.12.64.4000 > 193.237.65.219.32833: . 3059:4507(1448) ack 74 win 5792 <nop,nop,timestamp 18897529 1802225> (DF)
20:49:44.319159 > 193.237.65.219.32833 > 217.33.12.64.4000: . 74:74(0) ack 4507 win 14480 <nop,nop,timestamp 1803426 18897529> (DF)
20:49:49.561886 < 217.33.12.64.4000 > 193.237.65.219.32833: . 4507:5955(1448) ack 74 win 5792 <nop,nop,timestamp 18897529 1802225> (DF)
20:49:49.561979 > 193.237.65.219.32833 > 217.33.12.64.4000: . 74:74(0) ack 5955 win 17376 <nop,nop,timestamp 1803950 18897529> (DF)
20:49:54.823304 < 217.33.12.64.4000 > 193.237.65.219.32833: . 5955:7403(1448) ack 74 win 5792 <nop,nop,timestamp 18897529 1802225> (DF)
20:49:54.823394 > 193.237.65.219.32833 > 217.33.12.64.4000: . 74:74(0) ack 7403 win 20272 <nop,nop,timestamp 1804477 18897529> (DF)
20:50:00.072892 < 217.33.12.64.4000 > 193.237.65.219.32833: . 7403:8851(1448) ack 74 win 5792 <nop,nop,timestamp 18898211 1802902> (DF)
20:50:00.072990 > 193.237.65.219.32833 > 217.33.12.64.4000: . 74:74(0) ack 8851 win 23168 <nop,nop,timestamp 1805002 18898211> (DF)
20:50:05.341269 < 217.33.12.64.4000 > 193.237.65.219.32833: . 8851:10299(1448) ack 74 win 5792 <nop,nop,timestamp 18898211 1802902> (DF)
20:50:05.341362 > 193.237.65.219.32833 > 217.33.12.64.4000: . 74:74(0) ack 10299 win 26064 <nop,nop,timestamp 1805528 18898211> (DF)
20:50:10.602470 < 217.33.12.64.4000 > 193.237.65.219.32833: P 10299:11747(1448) ack 74 win 5792 <nop,nop,timestamp 18898735 1803426> (DF)
20:50:10.602561 > 193.237.65.219.32833 > 217.33.12.64.4000: . 74:74(0) ack 11747 win 28960 <nop,nop,timestamp 1806054 18898735> (DF)
20:50:14.272884 < 217.33.12.64.4000 > 193.237.65.219.32833: P 11747:12722(975) ack 74 win 5792 <nop,nop,timestamp 18898735 1803426> (DF)
20:50:14.272983 > 193.237.65.219.32833 > 217.33.12.64.4000: . 74:74(0) ack 12722 win 31856 <nop,nop,timestamp 1806422 18898735> (DF)
20:50:19.523616 < 217.33.12.64.4000 > 193.237.65.219.32833: . 12722:14170(1448) ack 74 win 5792 <nop,nop,timestamp 18899260 1803950> (DF)
20:50:19.523710 > 193.237.65.219.32833 > 217.33.12.64.4000: . 74:74(0) ack 14170 win 34752 <nop,nop,timestamp 1806947 18899260> (DF)
20:50:24.785028 < 217.33.12.64.4000 > 193.237.65.219.32833: . 14170:15618(1448) ack 74 win 5792 <nop,nop,timestamp 18899260 1803950> (DF)
20:50:24.785119 > 193.237.65.219.32833 > 217.33.12.64.4000: . 74:74(0) ack 15618 win 37648 <nop,nop,timestamp 1807473 18899260> (DF)
20:50:30.032878 < 217.33.12.64.4000 > 193.237.65.219.32833: . 15618:17066(1448) ack 74 win 5792 <nop,nop,timestamp 18899787 1804477> (DF)
20:50:30.032969 > 193.237.65.219.32833 > 217.33.12.64.4000: . 74:74(0) ack 17066 win 40544 <nop,nop,timestamp 1807998 18899787> (DF)
20:50:35.302882 < 217.33.12.64.4000 > 193.237.65.219.32833: . 17066:18514(1448) ack 74 win 5792 <nop,nop,timestamp 18899787 1804477> (DF)
20:50:35.302970 > 193.237.65.219.32833 > 217.33.12.64.4000: . 74:74(0) ack 18514 win 43440 <nop,nop,timestamp 1808525 18899787> (DF)
20:50:40.562865 < 217.33.12.64.4000 > 193.237.65.219.32833: . 18514:19962(1448) ack 74 win 5792 <nop,nop,timestamp 18900315 1805002> (DF)
20:50:40.562955 > 193.237.65.219.32833 > 217.33.12.64.4000: . 74:74(0) ack 19962 win 46336 <nop,nop,timestamp 1809051 18900315> (DF)
20:50:45.792976 < 217.33.12.64.4000 > 193.237.65.219.32833: . 19962:21410(1448) ack 74 win 5792 <nop,nop,timestamp 18900315 1805002> (DF)
20:50:45.793066 > 193.237.65.219.32833 > 217.33.12.64.4000: . 74:74(0) ack 21410 win 49232 <nop,nop,timestamp 1809574 18900315> (DF)
20:50:51.552902 < 217.33.12.64.4000 > 193.237.65.219.32833: P 21410:22858(1448) ack 74 win 5792 <nop,nop,timestamp 18900851 1805528> (DF)
20:50:51.552994 > 193.237.65.219.32833 > 217.33.12.64.4000: . 74:74(0) ack 22858 win 52128 <nop,nop,timestamp 1810150 18900851> (DF)
20:50:56.792977 < 217.33.12.64.4000 > 193.237.65.219.32833: . 22858:24306(1448) ack 74 win 5792 <nop,nop,timestamp 18900851 1805528> (DF)
20:50:56.793066 > 193.237.65.219.32833 > 217.33.12.64.4000: . 74:74(0) ack 24306 win 55024 <nop,nop,timestamp 1810674 18900851> (DF)
20:51:02.032865 < 217.33.12.64.4000 > 193.237.65.219.32833: . 24306:25754(1448) ack 74 win 5792 <nop,nop,timestamp 18901377 1806054> (DF)
20:51:02.032955 > 193.237.65.219.32833 > 217.33.12.64.4000: . 74:74(0) ack 25754 win 57920 <nop,nop,timestamp 1811198 18901377> (DF)
20:51:07.242888 < 217.33.12.64.4000 > 193.237.65.219.32833: . 25754:27202(1448) ack 74 win 5792 <nop,nop,timestamp 18901377 1806054> (DF)
20:51:07.242982 > 193.237.65.219.32833 > 217.33.12.64.4000: . 74:74(0) ack 27202 win 60816 <nop,nop,timestamp 1811719 18901377> (DF)
20:51:12.962860 < 217.33.12.64.4000 > 193.237.65.219.32833: . 27202:28650(1448) ack 74 win 5792 <nop,nop,timestamp 18901743 1806422> (DF)
20:51:12.962946 > 193.237.65.219.32833 > 217.33.12.64.4000: . 74:74(0) ack 28650 win 63712 <nop,nop,timestamp 1812291 18901743> (DF)
20:51:18.182724 < 217.33.12.64.4000 > 193.237.65.219.32833: . 28650:30098(1448) ack 74 win 5792 <nop,nop,timestamp 18901743 1806422> (DF)
20:51:18.182819 > 193.237.65.219.32833 > 217.33.12.64.4000: . 74:74(0) ack 30098 win 63712 <nop,nop,timestamp 1812813 18901743> (DF)
20:51:21.822887 < 217.33.12.64.4000 > 193.237.65.219.32833: P 30098:31062(964) ack 74 win 5792 <nop,nop,timestamp 18902269 1806947> (DF)
20:51:21.822974 > 193.237.65.219.32833 > 217.33.12.64.4000: . 74:74(0) ack 31062 win 63712 <nop,nop,timestamp 1813177 18902269> (DF)
20:51:21.890387 > 193.237.65.219.32833 > 217.33.12.64.4000: P 74:82(8) ack 31062 win 63712 <nop,nop,timestamp 1813183 18902269> (DF)
20:51:22.922519 < 217.33.12.64.4000 > 193.237.65.219.32833: . 31062:31062(0) ack 82 win 5792 <nop,nop,timestamp 18908505 1813183> (DF)
20:51:22.922527 < 217.33.12.64.4000 > 193.237.65.219.32833: P 31062:31068(6) ack 82 win 5792 <nop,nop,timestamp 18908507 1813183> (DF)
20:51:22.922648 > 193.237.65.219.32833 > 217.33.12.64.4000: . 82:82(0) ack 31068 win 63712 <nop,nop,timestamp 1813287 18908507> (DF)
20:51:22.948645 > 193.237.65.219.32833 > 217.33.12.64.4000: P 82:88(6) ack 31068 win 63712 <nop,nop,timestamp 1813289 18908507> (DF)
20:51:23.992468 < 217.33.12.64.4000 > 193.237.65.219.32833: P 31068:31074(6) ack 88 win 5792 <nop,nop,timestamp 18908616 1813289> (DF)
20:51:23.992475 < 217.33.12.64.4000 > 193.237.65.219.32833: F 31074:31074(0) ack 88 win 5792 <nop,nop,timestamp 18908616 1813289> (DF)
20:51:23.992729 > 193.237.65.219.32833 > 217.33.12.64.4000: F 88:88(0) ack 31075 win 63712 <nop,nop,timestamp 1813394 18908616> (DF)
20:51:25.012863 < 217.33.12.64.4000 > 193.237.65.219.32833: . 31075:31075(0) ack 89 win 5792 <nop,nop,timestamp 18908718 1813394> (DF)