cancel
Showing results for 
Search instead for 
Did you mean: 

Plusnet firewall setting low blocks port 25

phildotc
Newbie
Posts: 1
Registered: 09-09-2013

Plusnet firewall setting low blocks port 25

Hello all. I thought I would put a post on here to prevent anyone else having the frustration and time wasted that I have for the past few months with regard to my self hosted internal SMTP server.
I have a static IP address and I have an SMTP server running on a machine at home. The necessary DNS settings are all in place at my domain host to toward email to the static IP address. Port 25 is forwarded on my router. This worked fine until a few months back when my incoming mail stopped arriving.
I contacted Plusnet and asked them what had changed their end, nothing was the answer. I then suspected my SMTP server switched back to using pop3 (which worked) and spent several hours trying to work out what had changed at my end. Nothing.
Contacted plus net again and got a new router as my old one was very old and not one supplied by Plusnet. Replaced the new router set up port forwarding still no success. Contacted Plusnet again and asked if they could be blocking port 25. Answer, "no, we don't block anything, it is not our place to filter internet traffic coming to your static address". Lived with the situation for a month or so but not ideal using pop3 for reasons I won't go into here.
Last week tried again, switched on logging on the router to see if my test emails were getting to the router. Nothing. Contacted Plusnet again, they wanted to start playing with my MS Outlook settings! I asked to speak to someone who understood DNS, port forwarding etc,  Finally got to speak to the techie who was "floor walking" at the time and explained the situation.
"Let me see what ports our firewall blocks on it's low setting. Ah it is blocking port 25"! Eureka!
Why don't all the tech support staff know about their own firewall and what it blocks. I asked him to switch off the firewall at their end. Hey presto my mail starts arriving as it should!
So several months ago something did change at the Plusnet end. Either the firewall was switched on (possibly when I changed package to unlimited) or someone changed the settings for their "low" firewall setting. Time has been wasted by both Plusnet and myself simply because the handful of techies I spoke to didn't know that they DO block incoming ports on their firewall by default.
Moral to this story. If you suddenly stop receiving stuff you used to via your static IP address insist that Plusnet support look at the firewall settings at their end and make sure that it is not the culprit.
Phil
2 REPLIES
Community Veteran
Posts: 5,472
Thanks: 292
Fixes: 4
Registered: 11-08-2007

Re: Plusnet firewall setting low blocks port 25

It is also worth noting that if you change your broadband product (e.g. upgrade to 'Unlimited'), then it is worth re-checking the Plusnet Broadband Firewall,  as the product changeover process has been known to reset the firewall to whatever the default setting is at the time.
Community Gaffer
Community Gaffer
Posts: 17,650
Thanks: 642
Fixes: 162
Registered: 05-04-2007

Re: Plusnet firewall setting low blocks port 25

It looks as though the firewall was turned on by a member of staff in July to try and fix the problems you were having. I have no idea why they thought turning a firewall on would help unblock access to a certain port, and I'm sorry that it took so long to understand what was causing the issue.
I've sent feedback on to their line manager suggesting that they  re-read the information about the broadband firewall in case they get any future questions about it.
If this post resolved your issue please click the 'This fixed my problem' button
 Chris Parr
 Plusnet Staff