Skip Ribbon Commands
Skip to main content
Benoit s Corner

Benoit's corner

May 11
Office 365 – TCP/IP communication ports for Office 365 communication

This is a translation/adaptation of a very good post from my friend, Arnaud Alcabez (original post [in French]

This shows the TCP/IP communication ports which has to be allowed on proxy which doesn’t allow generic characters (such as *

TCP/IP communication ports required depends on the service you want to use/provide to your users; if you want to allow POP or IMAP access to Exchange mailboxes, you have to allow POP and/or IMAP communication ports:

  • IMAP access
    • TCP/143 – Default unencrypted connection
    • TCP/465 – TLS encrypted connection
    • TCP/993 – SSL encrypted connection
  • POP access
    • TCP/110 – Default unencrypted connection
    • TCP/995 – SSL encrypted connection


Communication ports used by Office 365 table

Protocol / Port


TCP 443
  • Active Directory Federation Services – Server role and Proxy role
  • Microsoft Online Services portal
  • ‘My Company’ portal
  • Microsoft Outlook (2007 & 2010) remote access (Outlook Anywhere)
  • Entourage 2008 & Outlook 2011 for Mac
  • Outlook Web Access
  • SharePoint Online
  • Lync 2010 client
TCP 25 Mail routing
TCP 587 SMTP relay
TCP 143/993 IMAP client and simple migration tool
TCP 995 POP 3
TCP 80 and TCP 443
  • Microsoft Directory Synchronization (DirSync)
  • Simple Exchange migration
  • Simple IMAP migration
  • Exchange Management Console
  • PowerShell
PSOM/TCP 443 Lync Online / Remote access to conference for anonymous and federated users
STUN/TCP 443 Lync Online / Outbound video/audio/application sharing
RTC/UDP 50000-59999
STUN/UDP/RTP 49152-55000
STUN/UDP/RTP 55001-61000
STUN/UDP/RTP 61001-65535
Lync Online / Outbound audio/video



You Internet Domain Name must be added in the Allow tab on your Edge server if you have one as well as

The edge server must be reachable from Internet through TCP 5061 port with a valid certificate


Office 365 IP addresses

Office 365 Services

IP Addresses

Exchange Online and SharePoint Online

FOPE Services (ForeFront Online Protection for Exchange) = – = – = – = – = – = – = – = – = – = –

Lync Online

Federation Services – (Microsoft Federation Gateway)

​Due to a bug in the product, anonymous comments is currently disabled

Sorry about that


There are no comments for this post.

​Privacy Information

This blog is using tracking code for analytics purpose.

No personal data are stored and maintained.

 ‭(Hidden)‬ Blog Tools


 Follow Me On

 Share This

 Translation Tool

Translate this page