Want to run your own mail server at your house, office, etc, but can’t because your Internet Service Provider blocks inbound port 25? First, let’s talk about why your ISP blocks Port 25, and then I will tell you a simple, cost effective solution.

Why?
In an attempt to control Spam and viruses, most Internet service providers block inbound and outbound port 25, which means you could experience technical problems when sending email i.e. it won’t work. If ISPs didn’t block outbound port 25, a computer could get infected with a virus and then that virus could could send out thousands, if not millions of spam emails – infecting lots of other computers and networks too.

How to check
It is easy to check to see if your ISP blocks Port 25. You can call and ask the ISP if they block port 25 it is best to specify Inbound or Outbound. If you do not want to deal with having to contact the ISP you can test port 25 Inbound yourself. To do so you need to have a server running on port 25 and port 25 port forwarded in your router and firewall. Once configured head over to canyouseeme.org, type 25 into the box and click “Check your Port” You will have to do this from the location of your network that you want to check. If it comes back with an error, chances are high that your ISP is blocking port 25.

My ISP Blocks Port 25, What can I do?
Don’t fret…. There is an easy solution if you want to run an email server at your house and your ISP blocks port 25. No-IP Reflector is a cost effective workaround. Reflector allows No-IP to be the primary mail exchanger for your domain. When an email destined for your domain arrives at our servers, we forward it on to your inbound mail server, which can be on a different (and unblocked) port of your choice. Not only does Reflector allow you to run your own mail server from home, but it also does extensive spam / virus scanning, so you don’t have to worry about dealing with spam, which can be a serious headache. Reflector also includes greylisting and customizable RBL (Real Blackhole Lists) lists. Reflector will also hold all of your emails for a max of 7 days if your mail server is unreachable. Our servers hold your emails until yours is back online and continuously attempts to resend the messages back to your server. How sweet is that?

Also, please note that if your ISP blocks outbound port 25 you will need to use an outbound SMTP server such as Alternate-Port SMTP which allows you to send out through our servers using a different port. Our outbound servers also have a PTR record created which will help you send to major mail providers.

Do what was once impossible — run your own mail server. Plus, until the end of March, all* email services are 25% off. (not valid on renewals – new service only) Use coupon code: MARCH25 during checkout.