Re: Disable ipv6?

[Greg Troxel <gdt%lexort.com@localhost>]

Jeff <pacavegano%odonian.org@localhost> writes:

> I am, indeed, on a residential ISP, and your guess may be correct.
>
> # telnet mail.netbsd.org 25
> Trying 2001:470:a085:999::25...
> telnet: Connect to address 2001:470:a085:999::25: : No route to host
> Trying 199.233.217.200...
> telnet: Unable to connect to remote host: Operation timed out
>
> I did run tcpdump, but I'm no networking master, and I don't see
> anything that stands out to me.

Probably you will see SYN going out, and perhaps nothing coming back.
You really should be seeing ICMP Admin Prohibited, at least arriving at
your router, but I would guess the ISP would just drop and not do that
correctly.  And your router may well not incoming-NAT-translate the ICMP
responses to SYN.

My ISP blocks outbound 25 and does not return ICMP Admin Prohibited, for
what it's worth.

So, the fact that telnet timed out I would say is definitive.

Your options are:

  figure out how to use some email account you have, and the outbound
  servers via submission (which is SMTP, on a different port, for MUA to
  first-hop MTA only, and ~never blocked except on crazy public wifi)

  set up a VPS and fiddle with transport maps to be able to use it as
  outbound

  get business service instead after checking that smtp works

  use some other way to report bugs

> I also tried '# traceroute -p 25
> mail.NetBSD.org' and that ended with:
>
> 13  mail.netbsd.org (199.233.217.200)  15.955 ms *  16.379 ms

traceroute is udp, and -p is the base, so it would have been udp port
38, which has nothing to do with blocking tcp port 25.