Blocking port 25 on Fiber connections

Internet access discussion, including Fusion, IP Broadband, and Gigabit Fiber!
13 posts Page 2 of 2
by ewhac » Mon Nov 11, 2019 10:59 am
Sorry; should have been more clear:

sysops wrote:
Fusion DSL with static IP should not have port 25 being blocked in either direction.

Correct; it doesn't. My SMTP server works fine. The discussion is that, if I move from Fusion DSL to gigabit fiber, not only will I lose static IP, I will also have port 25 blocked. The loss of static IP can sort-of kind-of be mitigated with dynamic DNS and a cooperative DNS host (such as Pair Domains). Port 25 blocking is rather more difficult to ignore.

The main thrust of my previous lament (okay, rant) was that I appreciate that there are likely business concerns that have prevented Sonic from making static IP and IPv6 available on fiber, but that these concerns have never been even obliquely articulated, and it's the lack of information on this point that's causing whiny grey-beards like me to perennially grouse in the fora.
by quasar » Thu Nov 21, 2019 2:53 pm
I just park my real mail server on a VPS and have my local systems use opensmtpd to relay mail through it with authentication since the dynamic IP precludes regular unauthed SMTP relay whitelisting configuration.
Something like this: https://cgar.github.io/posts/Simple-Ope ... Relay.html
by ewhac » Sun Nov 22, 2020 12:45 am
Necro!

So, couple of things. First: a year ago I wrote:
...I appreciate that there are likely business concerns that have prevented Sonic from making static IP [ ... ] available on fiber, but that these concerns have never been even obliquely articulated, [ ... ]

Mr. Jasper has since furnished a reason I'm satisfied with: viewtopic.php?f=10&t=16612&p=55645&hilit=static#p55645

Second, on the point of blocking port 25 (SMTP): Based on the discussion, I had assumed both inbound and outbound connections to port 25 were blocked. Evidently this isn't so:

Code: Select all

$ telnet 135.180.XX.XX smtp
Trying 135.180.XX.XX...
Connected to 135.180.XX.XX.
Escape character is '^]'.
220 smtp.ewhac.net ESMTP Postfix (Notice: Relaying prohibited.  Unauthorized relay attempts constitute theft of service and will be logged.)
QUIT
221 2.0.0 Bye
Connection closed by foreign host.

This kinda surprised me. Is this intentional? If inbound connections to port 25 are indeed supported, then I could reconfigure Postfix to push through a smarthost.
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