Xtra will start blocking port 25 (SMTP) from April 26

Forums › New Zealand Broadband › Xtra will start blocking port 25 (SMTP) from April 26

juha

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Topic # 7197 27-Mar-2006 13:14

Just heard about it.

http://www.geekzone.co.nz/blog.asp?blogid=22&postid=204

Good or bad? Suresh of Outblaze has some good points here:

http://www.circleid.com/posts/port_25_blocking_or_fix_smtp_and_leave_port_25_alone_for_the_sake_of_spam/

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Reply # 31607 27-Mar-2006 14:49

Its good I'm not with them, otherwise I'd probably disconnect.

My parents however will be affected by, as they use an email account on my webhost. I'll be sure to explain why they won't be able to send mail at home without changing the SMTP server and why they won't be able to send email on their laptop when they are out and not connected to Xtra (without paying xtra more, or changing their SMTP server again).

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juha

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Reply # 31609 27-Mar-2006 14:58

Maybe they can use the Message Submission port 567?

Wonder how this will affect users of T3G devices actually...? I'll be not a little bit hacked off if I can't send mail from my Apache to my own mail server with SMTP AUTH.

There's no way to use a different SMTP port either on the Apache.

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Reply # 31612 27-Mar-2006 17:00

So who's going to be the first in NZ to offer a local cheap AUTH SMTP service on non standard ports or is something already available? I know there are numerous overseas providers offering such a service.

juha

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Reply # 31613 27-Mar-2006 17:10

Slingshot via India?

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freitasm

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Reply # 31614 27-Mar-2006 17:18

juha: There's no way to use a different SMTP port either on the Apache.

You just have to define the server with the port: pop.yourserver.co.nz[:port#] and smtp.yourserver.co.nz[:port#] (without the [ ] of course).

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juha

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Reply # 31615 27-Mar-2006 17:21

Ahh... obviously. Well, not really.

Thanks.

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Reply # 31616 27-Mar-2006 17:32

Surely this isn't blocking *outgoing* port 25 connection attempts, but only incoming?

So that people can't run their own mailserver type-of-thing. This is fairly common, as the article mentions.

In my opinion, only insane people would try to run a SMTP server on a dynamically changing IP address. I know you can get around it using dyn-dns, but it's still flaky at best.

When they turn this on, no one (but people running their own incoming mail server) will notice.

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Reply # 31618 27-Mar-2006 18:21

It would only be effective if it was outgoing, to stop "wormy" Xtra customers from bombarding mail servers on the Internet. Incoming blocking makes no sense really, because as you say, only the insane run a mail server like that...

I think people will notice. The sky won't fall down as such, but I think the better solution would be to deal with infected customers rather than punking the Internet.

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Reply # 31619 27-Mar-2006 18:24

Hmmm. I am not on Xtra, and I run a mailserver - with relay for non-serviced domains switched off, of course.

I agree. It's not the case of fixing the standard, but cleaning up the mess. Blocking a standard port is just a non-solution since that's not the root cause.

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muppet

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Reply # 31622 27-Mar-2006 18:32

Are you allocated a static IP by your provider, or dynamic? Do you use the mailserver for incoming mail, or sending only?

My inital comments were aimed at people who use a dynamic IP address for their MX record, that's all.

I am on Xtra and run my own mailserver for outgoing mail, it seems this'll now be blocked as well as contacting my "static" mailserver. I'll ask to have this removed when it's turned on, otherwise I'll just set the mailserver (my static one) to listen on a different port as well and shut down my local outgoing SMTP server.

It still seems like a really stupid thing to do, but Juha makes a valid point so I can see them doing it. It's going to be a lot easier for them to field a couple of calls from techie people, as opposed to them actually having to contact infected customers (who let's face it are going to be pretty dumb)

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Reply # 31623 27-Mar-2006 18:39

I have a static IP address, and use it as the MX record for a couple of domains, no relay from outside to outside allowed (only from my internal network to outside and from outside to my internal network).

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Reply # 31624 27-Mar-2006 18:41

Yea, if I could get a static IP address I'd use it as a backup MX for my domains.

I know I could switch/shop around etc, but for reasons I won't go into there's not much point doing that :)

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Reply # 31625 27-Mar-2006 18:43

muppet: Are you allocated a static IP by your provider, or dynamic? Do you use the mailserver for incoming mail, or sending only?

Me? I'm one of those naughty people who use teh_int4rw3b for something else than downloading, so yes, fully functional and spam-besieged mail server here. Not on Xtra though. :)

muppet: I am on Xtra and run my own mailserver for outgoing mail, it seems this'll now be blocked as well as contacting my "static" mailserver. I'll ask to have this removed when it's turned on, otherwise I'll just set the mailserver (my static one) to listen on a different port as well and shut down my local outgoing SMTP server.

Xtra says that they'll make exceptions, as long as you can give a good reason for it.

muppet: It still seems like a really stupid thing to do, but Juha makes a valid point so I can see them doing it. It's going to be a lot easier for them to field a couple of calls from techie people, as opposed to them actually having to contact infected customers (who let's face it are going to be pretty dumb)

I prefer "slow learners" myself...

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timbo

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Reply # 31683 28-Mar-2006 22:29

freitasm:
You just have to define the server with the port: pop.yourserver.co.nz[:port#] and smtp.yourserver.co.nz[:port#] (without the [ ] of course).

Hey Mauricio, do you know what devices will this work on? Any mobile device with a client or just Windows Mobile?
cheers,
tim

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Reply # 31684 28-Mar-2006 22:33

This implementation is pretty much standard anywhere - browsers, ftp clients, etc. I know for sure this works in Windows Mobile, but of course some specific programmer may elect not to implement it. It's really the case to test on the target device - i.e. it should work by default...

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