knownports / Ports 800–1023 / Port 993

Port993

  • imapsIMAP over TLS protocol

IANA has registered port 993 to imaps on TCP; UDP 993 is held as reserved. The entry cites RFC 3501, RFC 8314 and RFC 9051; RFC 3501 and RFC 9051 also appear on 143 (imap); RFC 8314 on 465 (submissions) and 995 (pop3s). RFC 9051 obsoleted RFC 3501, so the registry lists both the old and the new document. It is the TLS counterpart of imap on port 143.

  1. 990ftps
  2. 991nas
  3. 992telnets
  4. 993imaps
  5. 1 free
  6. 995pop3s
  7. 996vsinet
  8. 997maitrd
TCP assignedUDP assignedreservedno entryAll 44 assigned numbers in ports 800–1023

Registry entries

ServiceProtocolsRegisteredModifiedRFCsOther specs
imapsTCP—Feb 22, 2021RFC 3501, RFC 8314, RFC 9051—

Cited RFCs

RFCTitlePublishedStatusLater changes
RFC 3501INTERNET MESSAGE ACCESS PROTOCOL - VERSION 4rev1March 2003Proposed Standardobsoleted by RFC 9051; updated by RFC 4466, RFC 4469, RFC 4551, RFC 5032, RFC 5182 and 8 more
RFC 8314Cleartext Considered Obsolete: Use of Transport Layer Security (TLS) for Email Submission and AccessJanuary 2018Proposed Standardupdated by RFC 8997
RFC 9051Internet Message Access Protocol (IMAP) - Version 4rev2August 2021Proposed Standard—

Listed in Ports that cite an RFC · Plain and TLS port pairs · Mail ports: smtp, submission, imap and pop3