FAQ Email

Which email ports should I use?

Every port number a mail client asks for, what each one is used for, and which ones to actually choose.

iFastHosting Support Team Updated 26 August 2026 4 min read Beginner

Every port below is a standard one, defined for the purpose it lists — none of them are specific to any one host or mail provider. Pick the encrypted option in each category and you will be right for almost any mail app on almost any device.

Purpose	Port	Encryption	Recommended?
Sending mail (SMTP)	587	STARTTLS	Yes — the standard default
Sending mail (SMTP)	465	SSL/TLS	Yes — use if an app specifically asks for SSL rather than STARTTLS
Sending mail (SMTP), unencrypted	25	None	No — used for server-to-server mail transfer, not for a mail client to send through
Receiving mail (IMAP)	993	SSL/TLS	Yes — the standard default
Receiving mail (IMAP), unencrypted	143	None	No
Receiving mail (POP3)	995	SSL/TLS	Only if you specifically need POP3
Receiving mail (POP3), unencrypted	110	None	No

Why 587 and not 25 for sending

Port 25 is used for mail servers to relay messages between each other across the internet, not for a mail client on a phone or computer to submit outgoing mail. Many networks and internet providers block outbound port 25 entirely for ordinary connections specifically because it is a common route for spam, which is one reason a mail client configured to use it can appear to work on one network and fail on another. Port 587 exists specifically for client submission, requires the mailbox's username and password, and is the port every mail app should be configured to send through.

465 versus 587

Both are valid encrypted options for sending, and the difference is in how the encryption is applied rather than in security: 465 encrypts the connection from the start, while 587 begins unencrypted and then upgrades using STARTTLS. Modern mail apps handle either correctly. Use 587 by default, and switch to 465 only if a specific app offers it as the SSL option and does not connect on 587.

Why the unencrypted ports should never be selected

Ports 143, 110 and unauthenticated 25 send your password in plain text

Selecting an unencrypted port for IMAP or POP3 sends your mailbox password over the connection without any encryption protecting it, readable by anything positioned to intercept the connection. There is no situation in normal mail client setup where this should be chosen over the encrypted equivalent — every current mail app supports the encrypted ports, and there is no downside to using them.

Where these ports are entered

Every mail app setup guide on this site — Outlook, iPhone, Android, and Apple Mail — asks for exactly these fields as part of manual setup, alongside the incoming and outgoing server names shown in your control panel.

If a connection fails on the correct port

Check the encryption setting matches the port — 993 and 995 both expect SSL/TLS; 587 expects STARTTLS specifically, and selecting the wrong encryption type for a given port is a common cause of a failed connection that looks identical to a wrong password.
Check whether your network blocks the port, particularly port 25 on many home and mobile networks, though this should not affect 587, 465, 993 or 995 under normal circumstances.
Confirm the server hostname is correct, since a wrong port on the right server and a right port on the wrong server both fail in similar ways.

If the ports and server names all check out but the connection still fails, fixing authentication failed errors covers the remaining causes, most of which come down to the password or account status rather than the port itself.