Postfix no longer receives or sends email that isn't to or from localhost

[Wsbs9GC]

I just double checked that I had port 25 in the rule and it was there for both tcp and udp. I am not sure that I disabled SElinux because of the error I received. How can I check that it was successfully disablled? I did run the command with sudo per your post.

[Wsbs9GC]

I just looked through my main.cf file and found that the relayhost parameter was blank so I provided smtp.comcast.net:587 as the value for that parameter and there was no change to the functionality of the mail server. I can still no longer send or receive. My thunderbird client now hangs when trying to submit an email and eventually fails connecting. Does anyone out there have any ideas on how to troubleshoot this issue? I really need a working email solution, preferably one that is done in house. I am not against paying for services to allow me to send and receive my mail but I'd like as much of the stuff to be kept in house as possible. Much thanks to anyone who reads this.

[Wsbs9GC]

Okay, so I think I fixed my own problem. It's probably a hackish solution, but if it works, that's all that matters. What I did was remove any of what I assumed to be temp files of main.cf from /etc/postfix/. they look like /etc/postfix/main.cf~n where n is a positive integer. Sometimes this n is absent, but the tilde stays. Then I edited the relayhost parameter as such:

relayhost = [smtp.comcast.net]:587

Here, to my knowledge, smtp.comcast.net is the smtp server that my ISP runs for its subscribers and 587 is the submission port. I also commented out this line

# smtp_sasl_mechanism_filter = login

I'm not sure that commenting it out did anything or what it does when it is left uncommented, but doing this allowed my setup to send mail. So in short, I can now send mail as I could before. I have no clue why it stopped working in the first place though. I'm still waiting on my email from an outside email domain to make sure that I can receive mail again. I'll update this thread once I either get a failure to deliver notice or it shows up in my inbox.

[Wsbs9GC]

Okay, so I can receive emails that are sent from my domain just fine. And I can send to my domain and other domains just fine. However it's been over an hour since I sent two emails from two other domains to my domain and they still have not arrived. Curiously, they haven't failed yet either. What do you think the problem is?