[Pkg-exim4-users] Problems concerning IPv6 Port 25's opening to the Internet

Satoru Otsubo trnsnt at otip.jp
Tue Nov 6 16:17:46 UTC 2012


Hi,
Marc

> 
> Again, please use telnet and tcpdump for more informative output.
> 

Although I have solved the problem, I here show you the following for your reference.

(1) tcpdump result at my PC:
  Two emails from debian-user at lists.debian.org are shown below:

otip:~# tcpdump -vv dst host  eeee:............:ffff and port 25
tcpdump: listening on eth0, link-type EN10MB (Ethernet), capture size 65535 bytes

22:20:17.996462 IP6 (hlim 46, next-header TCP (6) payload length: 40) bendel.debian.org.35372 >  eeee:............:ffff.smtp: Flags [S], cksum 0xa731 (correct), seq 163249803, win 5760, options [mss 1440,sackOK,TS val 589272526 ecr 0,nop,wscale 7], length 0
22:20:18.251828 IP6 (hlim 46, next-header TCP (6) payload length: 32) bendel.debian.org.35372 >  eeee:............:ffff.smtp: Flags [.], cksum 0x3197 (correct), seq 163249804, ack 4134116590, win 45, options [nop,nop,TS val 589272590 ecr 321065946], length 0
22:20:24.710972 IP6 (hlim 46, next-header TCP (6) payload length: 32) bendel.debian.org.35372 >  eeee:............:ffff.smtp: Flags [.], cksum 0x24ba (correct), seq 0, ack 66, win 45, options [nop,nop,TS val 589274204 ecr 321067560], length 0
22:20:24.711000 IP6 (hlim 46, next-header TCP (6) payload length: 56) bendel.debian.org.35372 >  eeee:............:ffff.smtp: Flags [P.], cksum 0x6680 (correct), seq 0:24, ack 66, win 45, options [nop,nop,TS val 589274204 ecr 321067560], length 24
22:20:24.966600 IP6 (hlim 46, next-header TCP (6) payload length: 128) bendel.debian.org.35372 >  eeee:............:ffff.smtp: Flags [P.], cksum 0xf40f (correct), seq 24:120, ack 191, win 45, options [nop,nop,TS val 589274268 ecr 321067624], length 96
22:20:25.222946 IP6 (hlim 46, next-header TCP (6) payload length: 1460) bendel.debian.org.35372 >  eeee:............:ffff.smtp: Flags [.], cksum 0xb0eb (correct), seq 120:1548, ack 269, win 45, options [nop,nop,TS val 589274332 ecr 321067688], length 1428
22:20:25.223235 IP6 (hlim 46, next-header TCP (6) payload length: 2700) bendel.debian.org.35372 >  eeee:............:ffff.smtp: Flags [P.], cksum 0x497c (incorrect -> 0x0337), seq 1548:4216, ack 269, win 45, options [nop,nop,TS val 589274332 ecr 321067688], length 2668
22:20:25.479045 IP6 (hlim 46, next-header TCP (6) payload length: 108) bendel.debian.org.35372 >  eeee:............:ffff.smtp: Flags [P.], cksum 0xec1c (correct), seq 4216:4292, ack 269, win 45, options [nop,nop,TS val 589274396 ecr 321067752], length 76
22:20:25.748741 IP6 (hlim 46, next-header TCP (6) payload length: 32) bendel.debian.org.35372 >  eeee:............:ffff.smtp: Flags [.], cksum 0x10e3 (correct), seq 4292, ack 334, win 45, options [nop,nop,TS val 589274464 ecr 321067819], length 0
22:20:25.748762 IP6 (hlim 46, next-header TCP (6) payload length: 32) bendel.debian.org.35372 >  eeee:............:ffff.smtp: Flags [F.], cksum 0x10e2 (correct), seq 4292, ack 334, win 45, options [nop,nop,TS val 589274464 ecr 321067819], length 0

22:20:37.523280 IP6 (hlim 46, next-header TCP (6) payload length: 40) bendel.debian.org.38561 >  eeee:............:ffff.smtp: Flags [S], cksum 0x154f (correct), seq 3417222899, win 5760, options [mss 1440,sackOK,TS val 589277407 ecr 0,nop,wscale 7], length 0
22:20:37.779638 IP6 (hlim 46, next-header TCP (6) payload length: 32) bendel.debian.org.38561 >  eeee:............:ffff.smtp: Flags [.], cksum 0xcd8c (correct), seq 3417222900, ack 1170541738, win 45, options [nop,nop,TS val 589277471 ecr 321070827], length 0
22:20:39.117078 IP6 (hlim 46, next-header TCP (6) payload length: 32) bendel.debian.org.38561 >  eeee:............:ffff.smtp: Flags [.], cksum 0xcaae (correct), seq 0, ack 66, win 45, options [nop,nop,TS val 589277805 ecr 321071162], length 0
22:20:39.117497 IP6 (hlim 46, next-header TCP (6) payload length: 56) bendel.debian.org.38561 >  eeee:............:ffff.smtp: Flags [P.], cksum 0x0c75 (correct), seq 0:24, ack 66, win 45, options [nop,nop,TS val 589277805 ecr 321071162], length 24
22:20:39.374282 IP6 (hlim 46, next-header TCP (6) payload length: 128) bendel.debian.org.38561 >  eeee:............:ffff.smtp: Flags [P.], cksum 0x9a04 (correct), seq 24:120, ack 191, win 45, options [nop,nop,TS val 589277869 ecr 321071226], length 96
22:20:39.632183 IP6 (hlim 46, next-header TCP (6) payload length: 4128) bendel.debian.org.38561 >  eeee:............:ffff.smtp: Flags [P.], cksum 0x4f10 (incorrect -> 0x2c0c), seq 120:4216, ack 269, win 45, options [nop,nop,TS val 589277934 ecr 321071290], length 4096
22:20:39.888401 IP6 (hlim 46, next-header TCP (6) payload length: 732) bendel.debian.org.38561 >  eeee:............:ffff.smtp: Flags [P.], cksum 0x0057 (correct), seq 4216:4916, ack 269, win 45, options [nop,nop,TS val 589277998 ecr 321071355], length 700
22:20:40.165338 IP6 (hlim 46, next-header TCP (6) payload length: 32) bendel.debian.org.38561 >  eeee:............:ffff.smtp: Flags [.], cksum 0xb462 (correct), seq 4916, ack 334, win 45, options [nop,nop,TS val 589278067 ecr 321071424], length 0
22:20:40.165359 IP6 (hlim 46, next-header TCP (6) payload length: 32) bendel.debian.org.38561 >  eeee:............:ffff.smtp: Flags [F.], cksum 0xb461 (correct), seq 4916, ack 334, win 45, options [nop,nop,TS val 589278067 ecr 321071424], length 0

(2) telnet result at the VPS through miredo tunnel:
  (As it is important for the HGW to make the ipv6-icmp protocol of my PC open to the Internet, in order to make "telnet" successful, I did so. Usually I am not opening the ipv6-icmp protocol of my PC to the Internet.)

# telnet  eeee:............:ffff 25
Trying  eeee:............:ffff...
Connected to  eeee:............:ffff.
Escape character is '^]'.
220 (my host) ESMTP Exim 4.72 Wed, 07 Nov 2012 00:30:45 +0900
^]
telnet> quit
Connection closed.

Thanks,
Satoru



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