I was recently preparing for Office 365 certification (exam 70-346), I came up with several questions about firewall ports used by O365. I explored and then I thought I should document for others 🙂

Ports Used by Office 365

Following are the ports used for various purposes by Office 365.

TCP 443 - ADFS, Microsoft Online Portal (Website), Outlook 2010, Outlook 2007, Outlook Web Access (Website), SharePoint Online (Website), Lync 2010 client

TCP 25 - Mail routing

TCP 587 - SMTP relay

TCP 143/993 - IMAP migration tool

TCP 995 - POP3

TCP 80 and 443 - Online services directory, simple exchange migration tool, simple IMAP migration

STUN/UDP 3478 - Lync Online (outbound audio and video session)

RTC/UDP 50000 - 59999 - Lync Online (outbound audio and video session)

TCP 50040 - 50059 - App sharing and file transfer

STUN/TCP 443 - Lync Online (outbound audio, video, and app sharing session)

TCP 443 - Lync (Data sharing sessions)

TCP 5223 - Lync Mobile Push iOS only


Firewall Ports Used by Office 365

Karim Buzdar

About the Author: Karim Buzdar holds a degree in telecommunication engineering and holds several sysadmin certifications. As an IT engineer and technical author, he writes for various web sites. You can reach Karim on LinkedIn

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