Comments on: Memo to ISPs: The SPAM Problem is Partly Your Fault

By: Casey Woods

Casey Woods — Wed, 18 Jun 2008 19:53:04 +0000

I’m glad to hear that Shaw is finally getting their act together on the port 25 issue. I’ve been using port 587 via smtp.gmail.com for years so I hadn’t noticed…

By: Randy

Randy — Wed, 18 Jun 2008 19:31:46 +0000

Shaw has had port 25 blocked for some time. Since at least August 2007 in Calgary. If you are sending Email from Shaw’s network, you have to use an alternate port.

Telus allows using port 1025 for their hosted email.

Shaw prevents email connections from outside their network altogether. You can’t use your Shaw (personal) email except through their web email.

I don’t know when they turned on port 25 blocking, but it’s definitely on at this time.

By: Robot Terror

Robot Terror — Fri, 07 Dec 2007 23:43:28 +0000

>> There is clearly a ton of SPAM originating from the Shaw network. <<

I laughed when I saw this. I work as a Linux System Admin for a major Internet hosting company. Very often when I am tracing yet more spam in a customer’s queue I find the source being an IP belonging to Shaw. I had never heard of Shaw until I started tracing spam back to exploited hosts.

For those ISPs that do block port 25, getting around the ISP blocks can be as simple as requesting an exception from the ISP or setting up a NAT rule or another smtpd service listening on an alternate port on the mail server (assumes complicity on the part of the Internet-hosted mail server that will relay your mail).

Whether ISPs should be blocking ports is a big question. But that Shaw is a contributing source of spam on the Internet…there is no doubt.

By: Casey Woods

Casey Woods — Sat, 01 Sep 2007 18:46:55 +0000

The problem is not the SMTP servers. The problem is the millions of security-swiss-cheez Windows machines that are spewing out SPAM like there is no tomorrow on port 25. I appreciate that you want to be able to run a SMTP server and have full access to outbound port 25, but you are in the 0.1% minority who requires this.

By: Blogs For Money

Blogs For Money — Sat, 01 Sep 2007 18:37:08 +0000

“Yet, a lot of ISPs continue to allow their customers to send email out to the world on TCP port 25 with no restrictions. Huh?”

I won’t use an ISP that wouldn’t allow this. I pay them for a connection, and I expect it to be un tampered with. The SMTP servers need locking down, not our access to them. I used to run my own mailserver at home (my ISP, Plusnet not only allows this, but can deliver mail their recieve for me to it!), and without being able connect out to any SMTP server, I wouldn’t have been able to delivery emails.

I note the above commenter changed to Smarthost, but that simple means all the spam is channeled through the smart host – it’s nto blocked. The only advantage to this is that it stops any viruses that try to deliver mail themselves (which I suspect is very few).

By: Casey Woods

Casey Woods — Fri, 25 May 2007 05:20:08 +0000

I was purely referring to home based business users. I do believe that business customers should not have to deal with port 25 filtering.

By: Johan

Johan — Wed, 23 May 2007 11:12:26 +0000

I totally agree with your point of view, but I have to admit that I was annoyed when my ISP (bredbandsbolaget) turned off outgoing SMTP. At that time, I was running my own mailserver, and I was not happy. Anyway, configuring my mailserver to use their server as smarthost wasn’t that difficult, and nowadays I don’t bother running my own server. Of course, this only applies to home broadband users, if you have business customers you probably need to allow them outgoing SMTP, even though it’s not really necessary for them either.
Still, as far as I know, here in Sweden most ISPs still allow outgoing SMTP, but they really shouldn’t. Blocking outgoing SMTP is a really simple solution, that doesn’t require a lot of resources or fancy filtering platforms, just an access-list.