From: lesen@wimezu.com
Lesley Esen writes:
> Marco Moock writes:
>
>> On 18.10.2024 um 11:03 Uhr Lesley Esen wrote:
>>
>>> Subject: outgoing tcp port 25 blocked? how to prove it?
>>
>> Use traceroute -T -p 25
>> Check where the last reply comes from.
>>
>> You can test with srv1.dorfdsl.de, this should reply in all cases.
>
> FreeBSD's traceroute doesn't have the -T option. So I don't know
> informative this will be. (I'm just learning about the -T and -p
> options. It seems very interesting and I don't know yet how it
> works.)
I installed tcptraceroute on FreeBSD. Here's the output. I'm puzzled
as to the result. It seems to reach srv1.dorfdsl.de (82.139.196.13) at
hop 16, but it continues on without getting any answer from who knows
what until it gives up. (Let me know if you'd like to see the reverse
DNS of each hop.)
%sudo tcptraceroute -n -p 25 srv1.dorfdsl.de
Selected device ena0, address 172.26.5.226, port 25 for outgoing packets
Tracing the path to srv1.dorfdsl.de (82.139.196.13) on TCP port 80 (http), 30
hops max
1 * * *
2 240.0.228.66 0.261 ms 0.212 ms 0.336 ms
3 242.2.121.195 1.631 ms 0.556 ms 11.656 ms
4 240.3.184.11 1.429 ms 1.416 ms 1.431 ms
5 242.10.90.51 8.191 ms 1.416 ms 1.214 ms
6 204.68.252.113 1.128 ms 1.145 ms 1.116 ms
7 * * *
8 154.54.40.49 1.571 ms 1.543 ms 1.556 ms
9 154.54.30.42 6.534 ms 6.779 ms 6.718 ms
10 154.54.30.186 72.423 ms 72.448 ms 72.587 ms
11 154.54.56.94 86.317 ms 86.475 ms 86.257 ms
12 154.54.62.229 89.603 ms 89.564 ms 89.571 ms
13 78.41.51.246 90.505 ms 90.580 ms 90.739 ms
14 78.41.51.91 87.700 ms 87.002 ms 86.761 ms
15 78.41.51.133 87.272 ms 87.397 ms 87.344 ms
16 82.139.196.13 129.743 ms 102.913 ms 101.489 ms
17 * * *
18 * * *
19 * * *
20 * * *
21 * * *
22 * * *
23 * * *
24 * * *
25 * * *
26 * * *
27 * * *
28 * * *
29 * * *
30 * * *
Destination not reached
%
> I cannot reach srv1.dorfdsl.de.
>
> --8<-------------------------------------------------------->8---
> %telnet srv1.dorfdsl.de 25
> Trying 82.139.196.13...
> telnet: connect to address 82.139.196.13: Operation timed out
> Trying 2a01:170:118f:3::22...
> telnet: connect to address 2a01:170:118f:3::22: No route to host
> telnet: Unable to connect to remote host
> %
> --8<-------------------------------------------------------->8---
>
> BTW, I don't know why modern telnet always tries an IPv6 in such cases.
>
> (*) The traceroute to srv1.dorfdsl.de
>
> --8<-------------------------------------------------------->8---
> %traceroute -p 25 srv1.dorfdsl.de
> traceroute to srv1.dorfdsl.de (82.139.196.13), 64 hops max, 40 byte packets
> 1 * * *
> 2 240.0.228.67 (240.0.228.67) 0.272 ms
> 240.0.228.64 (240.0.228.64) 0.254 ms
> 240.0.228.65 (240.0.228.65) 0.246 ms
> 3 242.2.120.71 (242.2.120.71) 0.856 ms 1.913 ms
> 242.2.120.195 (242.2.120.195) 1.009 ms
> 4 240.3.180.10 (240.3.180.10) 0.880 ms
> 240.3.180.11 (240.3.180.11) 0.935 ms
> 240.3.180.9 (240.3.180.9) 1.526 ms
> 5 242.10.82.177 (242.10.82.177) 1.471 ms
> 242.10.90.183 (242.10.90.183) 2.239 ms
> 242.2.213.197 (242.2.213.197) 1.199 ms
> 6 38.32.206.149 (38.32.206.149) 0.604 ms
> 100.100.4.78 (100.100.4.78) 1.399 ms
> 204.68.252.113 (204.68.252.113) 1.151 ms
> 7 * * *
> 8 be3083.ccr41.dca01.atlas.cogentco.com (154.54.30.53) 56.042 ms
> be3084.ccr42.dca01.atlas.cogentco.com (154.54.30.65) 2.441 ms
> port-channel5392.ccr92.dca04.atlas.cogentco.com (154.54.40.49) 1.736 ms
> 9 port-channel5042.ccr92.dca04.atlas.cogentco.com (154.54.162.221)
360.473 ms
> port-channel5927.ccr92.dca04.atlas.cogentco.com (154.54.163.101) 1.882
ms
> port-channel5042.ccr92.dca04.atlas.cogentco.com (154.54.162.221)
371.716 ms
> 10 be4188.ccr42.jfk02.atlas.cogentco.com (154.54.30.122) 58.424 ms
> be2317.ccr41.lon13.atlas.cogentco.com (154.54.30.186) 72.891 ms
> be2490.ccr42.lon13.atlas.cogentco.com (154.54.42.86) 72.750 ms
> 11 be2490.ccr42.lon13.atlas.cogentco.com (154.54.42.86) 72.794 ms 74.469
ms
> be12194.ccr41.ams03.atlas.cogentco.com (154.54.56.94) 86.506 ms
> 12 be12488.ccr42.ams03.atlas.cogentco.com (130.117.51.42) 131.634 ms
> be3874.rcr21.dus01.atlas.cogentco.com (154.54.62.229) 89.546 ms
> be12488.ccr42.ams03.atlas.cogentco.com (130.117.51.42) 88.654 ms
> 13 be3488.ccr42.lon13.atlas.cogentco.com (154.54.60.13) 92.094 ms
> be3875.rcr21.dus01.atlas.cogentco.com (154.54.73.25) 90.017 ms
> be3488.ccr42.lon13.atlas.cogentco.com (154.54.60.13) 92.073 ms
> 14 r0-36.00.3bw.tal.de (78.41.51.246) 90.619 ms 90.477 ms 90.669 ms
> 15 r4-68.bw.tal.de (78.41.51.91) 89.592 ms
> be3875.rcr21.dus01.atlas.cogentco.com (154.54.73.25) 91.501 ms
> r4-68.bw.tal.de (78.41.51.91) 87.113 ms
> 16 r1-3.bf.tal.de (78.41.51.133) 87.305 ms
> r4-68.bw.tal.de (78.41.51.91) 92.873 ms
> r1-3.bf.tal.de (78.41.51.133) 87.977 ms
> 17 srv1.dorfdsl.de (82.139.196.13) 112.620 ms * 97.974 ms
> %
> --8<-------------------------------------------------------->8---
>
> (*) Now from a host that is not blocked at all
>
> A telnet session first.
>
> --8<-------------------------------------------------------->8---
> %telnet srv1.dorfdsl.de 25
> Trying 2a01:170:118f:3::22...
> Connected to srv1.dorfdsl.de.
> Escape character is '^]'.
> 220 srv1.dorfdsl.de ESMTP Sendmail 8.17.1.9/8.17.1.9/Debian-2+deb12u2; Fri,
18 Oct 2024 19:37:36 +0200; (No UCE/UBE) logging access from: ko
testi.me(OK)-kontesti.me [IPv6:2600:3c03:0:0:f03c:91ff:fe96:40c1]
> quit
> 221 2.0.0 srv1.dorfdsl.de closing connection
> Connection closed by foreign host.
> %
> --8<-------------------------------------------------------->8---
>
> Now the traceroute. Looking at the traceroute, I can't tell the
> difference between this host and the blocked-FreeBSD one. Can you
> clarify that a little? Thanks!
>
> --8<-------------------------------------------------------->8---
> %sudo traceroute -T -p 25 srv1.dorfdsl.de
> [sudo] password for dbastos:
> traceroute to srv1.dorfdsl.de (82.139.196.13), 30 hops max, 60 byte packets
> 1 10.206.9.32 (10.206.9.32) 0.072 ms 0.075 ms 0.068 ms
> 2 10.206.35.101 (10.206.35.101) 0.211 ms 0.214 ms 10.206.35.102
(10.206.35.102) 0.226 ms
> 3 10.206.32.1 (10.206.32.1) 3.712 ms 3.718 ms 3.714 ms
> 4 lo0-0.gw1.cjj1.us.linode.com (173.255.239.101) 0.499 ms 0.377 ms
0.334 ms
> 5 ae37.r02.lga01.ien.netarch.akamai.com (23.203.156.50) 1.580 ms
ae31.r01.lga01.ien.netarch.akamai.com (23.203.156.16) 1.612 ms
e30.r02.ewr01.ien.netarch.akamai.com (23.203.154.42) 0.922 ms
[continued in next message]
--- SoupGate-Win32 v1.05
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