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Knowledgebase: outmail
What ports does MS Exchange use?


What ports does MS Exchange use?
Which TCP/UDP ports are used by Microsoft Exchange?


This knowledgebase articles details the TCP and UDP ports used by MS Exchange 2003, 2007 and 2010.

ProtocolPacket TypePortDescription
LDAPTCP389Lightweight Directory Access Protocol (LDAP), used by Active Directory, Active Directory Connector, and the Microsoft Exchange Server 5.5 directory.
 TCP379The Site Replication Service (SRS) uses TCP port 379.
 TCP390While not a standard LDAP port, TCP port 390 is the recommended alternate port to configure the Exchange Server 5.5 LDAP protocol when Exchange Server 5.5 is running on a Microsoft Windows Active Directory domain controller.
 TCP3268Global catalog. The Windows Active Directory global catalog (which is really a domain controller "role") listens on TCP port 3268. When you are troubleshooting issues that may be related to a global catalog, connect to port 3268 in LDP.
LDAP/SSLTCP636LDAP over Secure Sockets Layer (SSL). When SSL is enabled, LDAP data that is transmitted and received is encrypted.
 TCP3269Global catalog over SSL. Applications that connect to TCP port 3269 of a global catalog server can transmit and receive SSL encrypted data. To configure a global catalog to support SSL, you must install a Computer certificate on the global catalog.
IMAPTCP143Internet Message Access Protocol (IMAP), may be used by "standards-based" clients such as Microsoft Outlook Express, Live Mail, Mobile Devices to access the e-mail server. IMAP4 runs on top of the Microsoft Internet Information Service (IIS) Admin Service and enables client access to the Exchange Information Store.
IMAP/SSLTCP993IMAP4 over SSL uses TCP port 993. Before an Exchange server supports IMAP4 (or any other protocol) over SSL, you must install a Computer certificate on the Exchange 2000 server. This can be a self-signed certificate or a purchased signed certificate
POP3TCP110Post Office Protocol (POP3), enables "standards-based" clients such as Outlook Express, Windows Mail, Live Mail and other POP3 enabled mail clients to access the e-mail server. As with IMAP4, POP3 runs on top of the IIS Admin Service, and enables client access to the Exchange Information store.
POP3/SSLTCP995POP3 over SSL uses TCP port 995.
NNTPTCP119Network News Transport Protocol (NNTP), sometimes called Usenet protocol, enables client access to public folders in the Information store. As with IMAP4 and POP3, NNTP runs on top of the IIS Admin Service.
NNTP/SSLTCP563NNTPS over SSL uses TCP port 563.
HTTPTCP80Hyper-Text Transfer Protocol is the protocol used primarily by Microsoft Outlook Web Access (OWA)
SMTPTCP25Simple Mail Transfer Protocol (SMTP) is the foundation for all e-mail transport in Exchange. The SMTP Service (SMTPSvc) runs on top of the IIS Admin Service. Unlike IMAP4, POP3, NNTP, and HTTP, SMTP in Exchange does not use a separate port for secure communication (SSL), but uses a security sub-system called Transport Layer Security (TLS).
SMTP/SSLTCP465SMTP over SSL. TCP port 465 is reserved by common industry practice for secure SMTP communication using the SSL protocol. However SMTP typically still uses port 25 and use TLS for its security layer
SMTP/LSATCP691The Microsoft Exchange Routing Engine (RESvc) listens for routing link state information on TCP port 691. Exchange uses routing link state information to route messages and the routing table is constantly updated.
X.400TCP102TCP port 102 is the port that the Exchange message transfer agent (MTA) uses to communicate with other X.400-capable MTAs.
MS-RPCTCP135Microsoft Remote Procedure Call is a Microsoft implementation of remote procedure calls (RPCs). TCP port 135 is actually only the RPC Locator Service, which is like the registrar for all RPC-enabled services that run on a particular server. In Exchange 2000, the Routing Group Connector uses RPC instead of SMTP when the target bridgehead server is running Exchange 5.5. Also, some administrative operations require RPC. To configure a firewall to enable RPC traffic, many more ports than just 135 must be enabled.
ULSTCP522User Locator Service (ULS) is a type of Internet directory service for conferencing clients, such as NetMeeting. Exchange 2000 Server and Exchange 2000 Conferencing Server do not implement a ULS, but rather take advantage of Active Directory for directory services (by TCP port 389).
DNSUDP/TCP53Domain Name System (DNS) is at the heart of all of the services and functions of Windows Active Directory and Exchange Server.
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