A mail app reads your mail from the incoming server (IMAP) and sends through the outgoing one (SMTP). 22 of these 23 providers use port 993 with SSL/TLS for IMAP; for SMTP, 15 use port 465 with SSL/TLS and 7 use port 587 with STARTTLS. The table has each one's own, and each name links to its guide. The user name is usually your full email address, and many providers want an app password rather than the one you sign in to their website with.
Providers
| Provider | Incoming (IMAP) | Outgoing (SMTP) |
|---|---|---|
| AOL Mail | imap.aol.com993, SSL/TLS | smtp.aol.com465, SSL/TLS |
| AT&T Mail | imap.mail.att.net993, SSL/TLS | smtp.mail.att.net465, SSL/TLS |
| BT Email | mail.btinternet.com993, SSL/TLS | mail.btinternet.com465, SSL/TLS |
| CenturyLink Email | mail.centurylink.net993, SSL/TLS | smtp.centurylink.net587, STARTTLS |
| DreamHost Email | imap.dreamhost.com993, SSL/TLS | smtp.dreamhost.com587, STARTTLS |
| EarthLink Email | imap.earthlink.net993, SSL/TLS | smtpauth.earthlink.net587, STARTTLS |
| Fastmail | imap.fastmail.com993, SSL/TLS | smtp.fastmail.com465, SSL/TLS |
| Gmail | imap.gmail.com993, SSL/TLS | smtp.gmail.com465, SSL/TLS |
| GMX | imap.gmx.com993, SSL/TLS | mail.gmx.com587, STARTTLS |
| GoDaddy Professional Email | imap.secureserver.net993, SSL/TLS | smtpout.secureserver.net465, SSL/TLS |
| Hostinger Email | imap.hostinger.com993, SSL/TLS | smtp.hostinger.com465, SSL/TLS |
| iCloud Mail | imap.mail.me.com993, SSL/TLS | smtp.mail.me.com587, STARTTLS |
| IONOS Mail | imap.ionos.com993, SSL/TLS | smtp.ionos.com465, SSL/TLS |
| mail.com | imap.mail.com993, SSL/TLS | smtp.mail.com587, STARTTLS |
| Namecheap Private Email | mail.privateemail.com993, SSL/TLS | mail.privateemail.com465, SSL/TLS |
| Optimum Email | mail.optimum.net993, SSL/TLS | mail.optimum.net465, SSL/TLS |
| Proton Mail | 127.0.0.11143, STARTTLS Proton Mail Bridge, on your Mac | 127.0.0.11025, STARTTLS Proton Mail Bridge, on your Mac |
| Rackspace Email | secure.emailsrvr.com993, SSL/TLS | secure.emailsrvr.com465, SSL/TLS |
| Verizon email (in AOL Mail) | imap.aol.com993, SSL/TLS | smtp.verizon.net465, SSL/TLS |
| Windstream Email | imap.windstream.net993, SSL/TLS | smtp.windstream.net465, SSL/TLS |
| Xfinity Email | imap.comcast.net993, SSL/TLS | smtp.comcast.net587, STARTTLS |
| Yahoo Mail | imap.mail.yahoo.com993, SSL/TLS | smtp.mail.yahoo.com465, SSL/TLS |
| Zoho Mail | imap.zoho.com993, SSL/TLS | smtp.zoho.com465, SSL/TLS |
Each guide has the provider's other ports, POP3 where it offers it, and what to do if a mail app can't connect.
Ports
The standard ports, which most providers keep to. Your provider's own settings, in the table above, come first. What each means, and which to choose: IMAP ports, SMTP ports.
| Protocol | Port | Security | For |
|---|---|---|---|
| IMAP | 993 | SSL/TLS | Reading mail. Encrypted from the first byte. |
| IMAP | 143 | STARTTLS | Reading mail. Starts plain, then switches to encryption. |
| SMTP | 465 | SSL/TLS | Sending mail from an app. Encrypted from the first byte. |
| SMTP | 587 | STARTTLS | Sending mail from an app. Starts plain, then switches to encryption. |
| SMTP | 25 | — | Servers passing mail to each other. Many providers block it for mail apps. |
| POP3 | 995 | SSL/TLS | Downloading mail to one device. |
In LocalInbox
AOL Mail, Fastmail, Gmail, GMX, iCloud Mail, Proton Mail, Yahoo Mail and Zoho Mail are built in: choose the provider in Settings › Accounts › Add Account, and LocalInbox fills in its servers. For any other provider, choose Other IMAP account, open Server settings and type in the settings from the table. The same works in LocalInbox for iPhone and iPad.
Questions
Should I use IMAP or POP3?
IMAP, if your provider offers it. IMAP keeps your mail on the server, so read, moved and deleted messages look the same in webmail, on your phone and on your computer. POP3 downloads mail to one device, and what you do there doesn't show anywhere else.
What's the difference between SSL/TLS and STARTTLS?
Both encrypt the connection. With SSL/TLS (ports 993, 465 and 995) it's encrypted from the first byte; with STARTTLS (ports 143 and 587) the app connects in plain text and then asks to switch to encryption. RFC 8314 recommends SSL/TLS from the start where a provider offers it. Pick the one your provider lists for the port: the wrong kind for a port doesn't connect.
Why does my provider want an app password?
Gmail, iCloud Mail, Yahoo, AOL and others don't accept the password you sign in to their website with when a mail app signs in with a password. An app password is a separate one, made in your account's security settings for one app, which you can revoke without changing your main password. AT&T calls it a secure mail key.
Which providers does LocalInbox fill in by itself?
AOL Mail, Fastmail, Gmail, GMX, iCloud Mail, Proton Mail, Yahoo Mail and Zoho Mail: choose the provider in Settings › Accounts › Add Account and LocalInbox fills in the servers. For the rest, choose Other IMAP account and type in the settings from the table.