SMTP Port 25 issues?

Has anyone else had problems with sending mail on port 25? It was working fine early last week. I contacted tech support, who said I need to change everything to port 587.


It’s been working fine for literally years, and all of a sudden I have to change ports? Not to mention, I have copiers and other older devices that don’t allow me to change the default SMTP port.

Has anyone else run into this? Was there a service change bulletin I missed?

We aren’t blocking port 25, but your ISP or network administrator might be. You will need to contact them for details.

Unfortunately, no. I’m the NA, and according to our ISP at this location, nothing is being blocked.

On further investigation, it appears that not everyone is having this issue. Not exactly sure what’s going on, but I’m 70% certain it’s not DH now.

I am very curious, though, why the tech support person I was speaking with would tell me to make such a drastic change in our infrastructure. Ah well, I’ll chalk it up to a poorly trained support rep. Wouldn’t be the first time.

If it were indeed the case that your ISP were blocking port 25, then switching to port 587 would have been the appropriate fix. Most of the issues we encounter with customers being unable to send mail are the result of ISP port blocking, and are resolved by this change. It sounds as though you’re running into some other sort of issue, though — I’d be interested to hear details once you’ve got it figured out.

I have to tell you , I’ve been dealing with issues for 2 weeks now. Comcast states they haven’t blocked anything, yet I’ve had to switch back to port 25 from 587 after a year. Honestly I don’t think they have people manning their support who know anything about their infrastructure, however I was told I could pay extra for their support package and get help.

I’m stuck with using the webmail product for now until I can find a solution, but when your ISP lacks any urgency, it becomes an uphill battle. My suggestion is keep calling your ISP until you can get thru to someone who has 1/2 a brain.

did you test with port 587 to see if it solved your problem?

port 587 and the debates re? port 587 and port 25 have been around since Dec 1998 when the RFC for port 587 came into being:… or further reading you can also google “port 25 vs 587”.

I’ve had cases where windows virus software blocked port 25, you might also check that.

As far as equipment and devices go, are you positive you can’t change the port? I just looked at 2 brother Printer/fax/copiers and 1 HP and all had the ability to switch SMTP ports? port 25 blocking issues have been around forever.

No, it’s definitely NOT on our end. I just got back from another location…which uses a different ISP (also on a business account not blocking port 25), having the same issue…on ONE pc. One other pc was having the same issue, then miraculously started working again.

I get back to my office and my laptop (which is using port 587 since I take it out of the office), and for some reason can’t send email MYSELF now.

And now I see another thread for the same problem in the same time frame.