I just got off the phone with on of our partner ministries in Darwin. They have some visitor there right now and they were having troubles sending e-mail. They could receive e-mails, but they could not send e-mail.
After spending a good chunk of time checking the configuration of their router and their local computer and finding that they should be working fine we started to look at their Internet Service Provider (ISP).
I have started to notice a trend of Internet Service Providers blocking port 25 for their users. They do this for security reasons and also to prevent users from running servers on their Internet Connections. While this practice doesn’t normally happen on business connection we had a look into it anyways.
Sure enough after digging around the web-site for their ISP, iiNet, we determined that on their Broadband Internet Connections iiNet blocks port 25.
With iiNet it is pretty easy to open up the port. You just need to log into the iiNet toolbox with your connection settings and then open up the port.
Hopefully if you have same problem you can fix it that easily as well, or you might need to make a phone call to your Internet Service Provider.
Technorati Tags: isp, iinet, blocked port, port 25, smtp