POP3 vs IMAP

Use IMAP for any mailbox opened on two or more devices: it keeps the mail on the server, so phone, laptop and webmail show the same folders and the same read state. Use POP3 only for a single machine, a tight quota or an offline archive — it downloads mail to one device and, unless you switch on leave-a-copy, deletes the server copy afterwards.

• IMAP: folders, read flags and deletions happen on the server; every client sees the result.
• POP3: the client decides locally what to keep; the server forgets once mail is downloaded.
• Neither sends mail — that is SMTP, explained in what an SMTP server does.
• Both encrypt: IMAP over TLS on port 993, POP3 over TLS on port 995, per the IANA registry.

IMAP leaves every message on the server and synchronises the state around it: which folder holds it, whether it is read, flagged or answered, and whether it has been deleted. A phone connecting an hour later sees the same folder tree, the same order and the same unread count as the laptop that read the mail first.

The cost is server storage and a little patience. Every attachment stays on the server until somebody deletes or archives it, so a shared mailbox fills faster than a POP3 one. Clients cache headers and usually bodies, but a search across tens of thousands of messages still asks the server, and on a slow link the folder list appears before the message body.

On cPanel mailboxes IMAP is on by default and needs no extra setup, and the same mail hostname serves both protocols: port 993 for IMAP, 995 for POP3. Mailbox sizes and plans sit on the business email hosting page.

Use the TLS ports for every connection: 993 for IMAP and 995 for POP3, with 587 STARTTLS (or 465 TLS on older clients) for outgoing SMTP. IANA registers 110, 143, 993 and 995 for these services; the plain ports still answer on most servers and still expose the password in clear text.

• Incoming IMAP: your mail hostname, port 993, SSL/TLS.
• Incoming POP3: your mail hostname, port 995, SSL/TLS.
• Outgoing SMTP: port 587 with STARTTLS, or 465 with SSL/TLS on older clients.
• Username: the full email address on a cPanel mailbox, not just the part before the @.
• Plain ports 110 and 143: only inside a trusted network, and never with a reused password.

If port 993 is blocked, try 143 with STARTTLS before deciding the server is down — office and campus firewalls in India block 993 more often than 143, and STARTTLS gives the same encryption over the other port.

Keep the POP3 account in place until the new IMAP account has finished syncing, and export the local mail file before touching anything. The full walk-through, including the Outlook PST import order that avoids mail landing in a folder that never syncs, is in moving email accounts between hosts and devices; the short version runs:

1. Export the mailbox from the client first — in Outlook: File, Open & Export, Import/Export, Export to a file — and name the file with the date.
2. Confirm the mailbox settings in cPanel under Email Accounts, then Connect Devices, which lists the exact hostname and ports.
3. Add the same address as a new IMAP account on port 993; leave the POP3 account present and let it delete nothing.
4. After the first sync finishes, drag the local POP3 folders into the IMAP tree, creating the destination folder on the server first.
5. Send a test message from another address and confirm it appears in webmail and on the phone; keep the old account disabled but present for 30 days.

You know the move worked when a message read on the phone shows as read in webmail, and both Sent folders hold the same items. Everyday setup questions — aliases, signatures, webmail — are covered in the business email setup guide.