My SMTP Server is slow... how fix it?
Hello, I'm not that experienced with mail Servers but currently, I run an IMAP and SMTP Mailserver on my Linode. The IMAP connection etc. works lightning fast but the SMTP connection and email sending are extremely slow. What is the best to check what the issue is? And how can I fix that?
What service are you using to for your SMTP server? Sendmail, Postfix?
Without knowing that information, I would start by running the top command to see what your system resources are looking like. If there is a service consuming most of your system resources, I would recommend assessing that first as it may be causing this delay.
You may also want to check your mail queue, it's possible that may be filling up and causing the delay in your mail sending.
If you are using Sendmail you can try these commands:
$ sendmail -bp
If you are using Postfix, you can try these commands:
$ postqueue -p
If you are using Exim, you can try this command:
$ exim -bp
Once you assess your Mail queue, you can attempt to clear it out and start over to see if that helps. If the issue continues, you will want to identify what is causing that as it may be a result of a misconfiguration within your server.
I would also recommend checking your mail logs to see if they show any signs of potential issues. Here are some of the common file locations where these logs may exist:
I hope that helps!