I have an Exchange 2013 Server.
My ISP blocks port 25 and it doesn't seem to be working on any other port either.
I am currently using DynDNS' hosted SMTP service - but it only lets me send a few hundred with each subscription.
What is the best way of setting up something that would allow me to have an SMTP that works? Is there a way of setting up an Exchange server as some sort of relay server and then proxy the main send connector into it? Maybe in Azure?
Any decent internet provider will remove that block on a business account. Especially if you are paying for a static IP address, which would be best for running a mail server. Most probably will not remove it on residential accounts.
The blocks are to prevent spam and email viruses spreading. Since the vast majority wont be running their own mail server many ISPs block 25 by default as a safety measure. Of course if you have the block removed and start sending spam, your ISP will be having some words with you.
All you should have to do is call them up and tell them you are running your own mail server. It shouldn't take long or cost anything. If they won't remove the block, take your business elsewhere.
If they won't and you absolutely can't switch ISPs you can setup exchange to use a smarthost/relay, possibly to your ISPs server or to your own VPS somewhere on a nonstandard port. But it is usually best to avoid that and send it directly.
