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SMTP PORT 25 BLOCKED: I can receive but can not send email.

PostPosted: Wed Jan 26, 2005 12:04 pm
by tony
If you are able to receive email but not send, your SMTP Port(25) maybe blocked by your Internet Service Provider. Here is a simple test you can find out if this is the case. Open up a DOS Window Prompt (Click Start->Run then type cmd<enter>) and type:

telnet 25

Replace with your own domain name.

If you just see a blank screen then your ISP provider is blocking you.

Sympatico, Telus and a few other providers seems to be blocking this port to prevent spamming from their network.

Solution: You will need to get in contact with your ISP and see if they can remove this block. If not, you will have to send out your email with their mail server and have the reply field as your domain name email address.

PostPosted: Thu Mar 17, 2005 1:55 pm
by admin
This message has been moved here ....
Originally posted by DC Media

The resolution of the so called blocking of port 25 is an easy fix but one that Canadian Web Hosting is unwilling to undertake. It involves the configuration of the WHM (Web Host Manager) to install an additional copy of Exim (the script that handles mail transport) on a port that is not being blocked by the ISP.

Recent communication with Canadian Web Hosting has yielded the response that I am in someway confused with the concept of 'Working' as opposed to being 'Blocked'. What they fail to realize is that I am totally aware of what the situation is and what is required to handle the issue.

Yes Telus and others block port 25 outbound. Yes the mail server works at Canadian Web Hosting. However as 'Paid' users we are being told that in this situation we will be forced to have to use our ISP's outgoing mail server when we pay for the use of one? Something not right you say? Yes it is when tech support sends replies like the following:


You are mistaking not working with being blocked.

Our outgoing SMTP server works fine, its Telus that is blocking 3rd

party outgoing mail servers.

If you have issues with this, I suggest you contact Telus and get them

exclusively open up port 25 for you.


Telus and others won't make an exception on the port 25 issue unless you sign up for a business package and if that were the case, why would you need Canadian Web Hosting? Rediculous...

In my opinion the fix is simple and in no way compromises the integrity, security or performance of the server. It is also my opinion that we as customers should not be told that we have to pay full price to utilize 50% of a feature.

My opinion has been presented and honestly I am looking elsewhere.

DC Media

PostPosted: Thu Mar 17, 2005 1:55 pm
by admin
And this one too...
and originally posted by D_Rayle

Interesting... I have been plagued by the same problems as well - and up until now had just learned to accept it. But a search of cpanel's forums shows the obvious solution, and that is to enable exim to listen on an alternate port. ... rnate+port

I am guessing that is only something that Canada Web Hosting can do in WHM on their end? and if so, why haven't they enabled it?

PostPosted: Thu Mar 17, 2005 3:16 pm
by tony
Sorry I was trying to move these to a new thread but ended up deleting it instead. I had our Forum admin post back what was lost.. but thank you for the input and I will answer your questions below:

Yes, it is true that Port 26 can be configured through the WHM in Cpanel. However, this port can also be blocked by your ISP very easily. As the Link provided by D_Rayle shows, Cox is already blocking port 26. Cpanel will only allow the configuration of the main port 25 and one other port. It is impossible to implement multiple ports which will satisfy everyone.

We have reviewed and discussed this solution on many occasions and have concluded that it is not a permanent fix and may even result in disgruntled customers later. It is in the best interest of our customers that they are provided with a working fix and not a quick patch that may break later.

In my opinion the fix is simple and in no way compromises the integrity, security or performance of the server. It is also my opinion that we as customers should not be told that we have to pay full price to utilize 50% of a feature.

This is a very good question.

For the first part, in order for the server to listen on port 26, another Exim process will need to be spawned. This will actually increase the server load and may degrade the server performance to some extent.. but this is not the reason why we did not enable port 26.

As to whether you are paying full price for a 50% service, you will need to contact your ISP and ask them why. Your hosting account comes with all the services and is available for your use. We are not able control what services are being blocked by your Service Provider. Let’s take this for example:

We have many customers that access their control panel running on port 2083 at work. I get approximately 3 - 5 support calls per day about not able to connect to the control panel. About 90% of them are using a company Internet Connection with a firewall that only allows certain ports to be accessed by their employees. When they get home though, everything works fine.

Our services are available to you but we have no control on what gets blocked and by whom. This is in the control of your ISP. Your Internet Service Provider is suppose to grant 100% access to the Internet, but it seems that they are blocking and limiting the connection, hence providing less than a Full Service. With how spam is increasing, this problem is just going to get worse. This is why we provide technical support which work with our services and your ISPs.

We look for a long term relationship with our clients so every network policy, every fix and every patch that we place on a server is reviewed.. This is to ensure the long term survivability of our services.

PostPosted: Wed Apr 20, 2005 7:16 pm
by crrj
I am with Hell, er Bell, business dial-up for my internet connection and it too has port 25 blocked.

I solved the issue by connecting with SSL which is a different port, no troubles.

PostPosted: Wed Jul 13, 2005 2:45 pm
by enterprise17
Rogers is now blocking port 25. But they suggest asking the hosting place to offer 587 since that port requires a username and password (like CWH did anyways with port 25) Is there any hope in this 587 option?

PostPosted: Fri Sep 02, 2005 1:54 pm
by valar2006

PostPosted: Sat Sep 03, 2005 5:04 pm
by admin
Well, not everyone has it blocked so we have to make sure it works for everybody.

Yes I know its not very convenient, but we're gonna leave things as is.


PostPosted: Thu Dec 08, 2005 5:38 pm
by ilsa
admin wrote:Well, not everyone has it blocked so we have to make sure it works for everybody.

Yes I know its not very convenient, but we're gonna leave things as is.


You're kidding, right? Let me get this straight... The biggest high-speed ISPs in canada (or at least Ontario) are blocking port 25. They will under no circumstances change that policy for home users.

And you won't open another port or setup SMTP+SSL?

The whole reason I set up an account with CWH is because you had proper SMTP server instead of POP3 only access like most other providers. If people can't access the port, then CWH is no better than the others.

I have had quite satisfactory service with CWH until all this took place. I've since had to make due with setting up parallel accounts with a free email provider that did SMTP, because that was the least hassle.

That service has now been discontinued, and I'm really sick of all the hoops I have to go through. Bell, Rogers and CWH are coming up with these rediculous email policies because they're more concerned about their own convenience rather than their customers.

Well, I've now cancelled my service with bell and moved to an ISP that doesn't block port 25. That will take effect hopefully next month.

And unless you people change your "we can't be bothered, sucks to be you" attitude, I'm going to be dumping you as well. In the past I've recommended you to friends and colleages, but you can be sure that this will change immediately.

PostPosted: Mon Jan 02, 2006 11:49 pm
by Maurice
It's unfortunate to see ilsa go, especially when this issue really is beyond CWH's control. Currently CWH is my backup hosting provider, but my main host HQ'ed in the U.S. faces the same problem with this port 25 thing and we, the clients, have come to understand that it's not their fault but the ISPs'.

One solution provided by my main host, which may or may not work here, is that users who find their outbound mail blocked on port 25 can try the secure port on 465; however, they will have to accept the certificate that appears. There is no guarantee even at my main host that using the secure port will be successful, as this depends on the ISP and if they have blocked it, too.

As to why ISPs do this, my main host explained the ISPs' rationale as follows:
"It's not [that ISPs are worried] about the hijacking of your connection to relay mail through our [the web host's] servers. It's about hijacking your system to spam through any open proxy they can find on any ISP. These days, it's even more of a problem given that spammers use trojans on compromised home [and small businesses'] systems, which actively search for open proxies to use via the user's own machine, [thus allowing] the spammer to hide their true location [and] making it impossible to trace them to their origination point and complain there. Instead, people will only see you and complain appropriately to the ISP, who, if they're smart, will shut you down.

Like my main host, CWH is not conspiring to block port 25 and make our lives more difficult.

~Maurice :roll:

PostPosted: Wed Aug 23, 2006 7:01 pm
by selva

What is the status of SMTP now? Is it possible to use SMTP with
TLS on port 465 or 587? Without that SMTP is pretty useless these
days when most ISP's block port 25 for third party servers.



P.S. I am trying to evaluate hosting solutions in Canada before
switching, so please bear with such questions.

Port 465 & Rogers

PostPosted: Thu Aug 31, 2006 8:54 am
by Masala

I think I just ran into the Port 25 issue on a Rogers account I switched the protocol for SMPT to use SSL, which runs on port 465, and it works sweetly. Possibly a better choice than vanilla SMTP anyway.

Using Thunderbird for a mail client, the change was quick and painless and my CWH account was pre-configured to support it, therefore it required no changes.

(I say "I think" I encountered the problem as the symptoms were the same - POP3 mail retrieval worked, but not sending via SMTP. Disabled both the PC's firewall and my hardware firewall, which didn't help. SMTP with SSL now works with both PC and hardware firewalls re-enabled. So it seems like Rogers was the likely culprit here).


PostPosted: Sun Sep 10, 2006 12:43 pm
by kevin
We have opened up SMTP port 26.

PostPosted: Wed Nov 08, 2006 3:30 pm
by mrplug
port 26, wow that helps me alot, i got employees out of town, and most isps in town block 25. thanks

PostPosted: Tue Mar 27, 2007 5:42 am
by shivin
Cool ...
Glad to know its working again. :D