Thomas Mueller wrote:
hi
customers phoned me that they could not send emails anymore. needed to switch to port 587.
Maybe there is something filtering between you and them. They should be using port 587 anyway which is supposed to be the submission port. Unless they are running a fullblown SMTP setup on a DSL link of course.
now heard from others that swisscom is blocking port 25 ??? what the heck is going on ?
Which "others" and what metrics do they have?
Works fine from my home link: 8<------------------------------------------------ jeroen@purgatory:~$ telnet -4 unfix.org 25 Trying 194.1.163.39... Connected to abaddon.unfix.org. Escape character is '^]'. 220 abaddon.unfix.org ESMTP Unfix ... ------------------------------------------------>8
You might want to fire up wireshark and see what is going on. If you are lucky you get an ICMP response and you can tell from that where it is being filtered...
Greets, Jeroen