Spark refusing to unblock port 25

Forums › Spark New Zealand (including Skinny and BigPipe) › Spark refusing to unblock port 25

iNs3ct

9 posts

Wannabe Geek

#175280 23-Jun-2015 18:07

Since when did Spark refuse to unblock port 25? Can somebody recommend another isp so i can send email again.

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856 posts

Ultimate Geek

#1330131 23-Jun-2015 18:15

It's to stop spammers.

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iNs3ct

9 posts

Wannabe Geek

#1330133 23-Jun-2015 18:22

And emailers apparantly

Psilan

856 posts

Ultimate Geek

#1330135 23-Jun-2015 18:29

The majority of email is spam, so yeah.

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raytaylor

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#1330143 23-Jun-2015 18:43

There appears to be a technical reason behind this

Their port 25 unblock service must be based upon the ip address of the source connection within their network.
Therefore you first need to have a static ip address assigned to you.

But it seems that the plan you have chosen doesnt qualify for a static ip address - probably for a future transition to CGNAT - though when i last looked a few years ago, telecom had an excessive pool of IPv4 address space.
But also it could be to prevent users running servers on home broadband connections.

The solution
You obviously have a domain if you are sending email directly, and probably have a web hosting company that provides an smtp relay service - so just use that on a port other than 25.

Ray Taylor

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Talkiet

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#1330163 23-Jun-2015 19:29

raytaylor: There appears to be a technical reason behind this

Their port 25 unblock service must be based upon the ip address of the source connection within their network.
Therefore you first need to have a static ip address assigned to you.

But it seems that the plan you have chosen doesnt qualify for a static ip address - probably for a future transition to CGNAT - though when i last looked a few years ago, telecom had an excessive pool of IPv4 address space.
But also it could be to prevent users running servers on home broadband connections.

The solution
You obviously have a domain if you are sending email directly, and probably have a web hosting company that provides an smtp relay service - so just use that on a port other than 25.

You're wrong on the conjecture about a transition to CGNAT. There are no current plans for that.

You're right about the underlying reason for the refusal to unblock port 25 though. It's clearly due to the unlimited plan not allowing static IP addresses. Now I THINK that has changed recently (don't quote me on that yet - I don't do product stuff) and if that's the case, then this will probably be an out of date rule somewhere that hasn't been updated. (I can't guarantee that it's not an actual product limitation sorry, but it seems odd on the surface)

I do know that the Static IP (even if available on unlimited) won't be free.

We don't have the technical capability built to enable unblocking of port 25 for customers that are on dynamic IP addresses, and we won't be looking at building it in the short term (or probably ever).

The reasons for the blanket block are probably reasonably well understood - but if not, can be summed up as "For security" :-)

I'm honestly pretty darn busy at the moment, but if you are able to secure a static IP, then the port 25 unblock should be available.

Cheers - N

Please note all comments are from my own brain and don't necessarily represent the position or opinions of my employer, previous employers, colleagues, friends or pets.

timmmay

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#1330168 23-Jun-2015 19:33

This is pretty standard and a fairly responsible thing for them to do, but unblocking for individual customers should be possible. Use SSL/TLS, which is on port 465. Or I guess change ISPs.

What email server are you trying to use?

iNs3ct

9 posts

Wannabe Geek

#1330173 23-Jun-2015 19:40

Thanks for the replies, I changed the port and it is working. Strange thing is that port 25 used to work just fine for me, and I wasn't on a static IP. I guess Spark has made some changes.

Cheers

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Talkiet

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#1330176 23-Jun-2015 19:43

Are you running mail server software or just using an SMTP server setting in an email client to send your emails?

Just in case anyone else is wondering, the Port 25 block stops you running a basic unencrypted MAIL SERVER on your connection, it shouldn't stop you sending email from an email client.

Cheers - N

Please note all comments are from my own brain and don't necessarily represent the position or opinions of my employer, previous employers, colleagues, friends or pets.

iNs3ct

9 posts

Wannabe Geek

#1330191 23-Jun-2015 19:54

If port 25 is blocked by spark and i'm not using their mail relay, then how could i send email from my mail client using port 25 smtp?

Talkiet

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#1330192 23-Jun-2015 19:55

Well, time to correct myself.. Thanks to CBRpilot who works more closely with the subscriber features than I do... There apparently have been a number of changes quite recently...

- Yes, we can unblock port 25 on dynamic IP now. Works just fine.
- The unlimited plans do allow static IP (I think at a cost) but DO NOT allow Port 25 unblocking. (That's the odd product limitation wiggle room I gave myself before)

This is a new thing and I'm unaware of the reasoning behind it sorry.

Cheers - N

Please note all comments are from my own brain and don't necessarily represent the position or opinions of my employer, previous employers, colleagues, friends or pets.

Talkiet

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#1330193 23-Jun-2015 19:56

iNs3ct: If port 25 is blocked by spark and i'm not using their mail relay, then how could i send email from my mail client using port 25 smtp?

Covered here...

http://www.spark.co.nz/help/internet-email/plans-services/port-25.html

Cheers - N

Please note all comments are from my own brain and don't necessarily represent the position or opinions of my employer, previous employers, colleagues, friends or pets.

iNs3ct

9 posts

Wannabe Geek

#1330195 23-Jun-2015 20:01

This is directly from the spark link mentioned above:

"How does Port 25 filtering work on the Spark network when it comes to sending email?

Port 25 filtering is a type of rule that checks the source IP address, destination IP address and destination Port before allowing the traffic. So it leaves only destination IP address to be checked. If you are using smtp.xtra.co.nz as your outgoing server, the destination IP address will be the IP address of that server (email is being sent to that server from the computer first) so filtering does not take place. But if you are using different server addresses, Port 25 is filtered."

Sounds kinda like outbound filtering to me.

cbrpilot

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Spark NZ

#1330205 23-Jun-2015 20:21

Spark's Port 25 filtering works both ways. Inbound and outbound port 25 is blocked.

My views are my own, and may not necessarily represent those of my employer.

BarTender

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#1330207 23-Jun-2015 20:23

I'm personally surprised anyone in this day and age needs port 25 unblocked.

You should be talking to your mail server over SSL so 465 or 587 would be the ports you use to connect so having port 25 blocked wouldn't impact you at all.

Having inbound port 25 means you are leaving yourself open as a spam relay. That's just bad (TM).

iNs3ct

9 posts

Wannabe Geek

#1330210 23-Jun-2015 20:26

Agreed, changing to SSL ports is a better solution than unblocking 25.

Thanks to everyone for your help 👍

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