This information is mostly for my own reference later on. I was looking up which ports I needed to open up in my IPTables configuration for my email server (which is also running nginx).
| service | port |
|---|---|
| http | 80 |
| https | 443 |
| smtp | 25 (2525 is an alternate) |
| pop3 | 110 |
| pop3-ssl | 995 |
| imap | 143 |
| imap-ssl | 993 |