SRV Record — Advanced Use Cases

What is an SRV Record?

An SRV (Service) record specifies the location — hostname and port — of servers for specific services. It allows service discovery via DNS, meaning software can automatically find where a service lives without hardcoding servers or ports. SRV records are used for things like SIP (VoIP), XMPP (chat), Minecraft servers, and Microsoft Teams/Office 365 integration.

_service._proto.name. TTL IN SRV priority weight port target.

# Example: SIP over TCP
_sip._tcp.example.com. 3600 IN SRV 10 20 5060 sipserver.example.com.
#                                   ^  ^   ^    ^
#                                   |  |   |    hostname
#                                   |  |   port
#                                   |  weight (load balancing)
#                                   priority (lower = preferred)

SRV Record Fields Explained

• ▸_service: The symbolic name of the service (e.g., _sip, _xmpp, _minecraft)
• ▸_proto: Protocol — _tcp or _udp
• ▸Priority: Lower value = higher priority. Clients try lowest priority first.
• ▸Weight: Used for load balancing among records with the same priority. Higher weight = more traffic.
• ▸Port: The port number the service listens on (e.g., 5060 for SIP, 25565 for Minecraft)
• ▸Target: The hostname of the server running the service. Must have an A/AAAA record.

Real-World Examples

Microsoft 365 / Teams

# Lync/Teams SIP Federation
_sipfederationtls._tcp.yourdomain.com. SRV 100 1 5061 sipfed.online.lync.com.

# Lync/Teams SIP
_sip._tls.yourdomain.com. SRV 100 1 443 sipdir.online.lync.com.

Minecraft Server Discovery

# Lets players connect to "play.yourdomain.com" instead of "yourdomain.com:25565"
_minecraft._tcp.play.yourdomain.com. SRV 0 5 25565 mc.yourserver.com.

XMPP (Jabber/Chat)

_xmpp-client._tcp.yourdomain.com. SRV 5 0 5222 xmpp.yourdomain.com.
_xmpp-server._tcp.yourdomain.com. SRV 5 0 5269 xmpp.yourdomain.com.

Common Mistakes

• ▸Setting target to an IP address instead of a hostname
• ▸Forgetting that the target hostname needs its own A record
• ▸Incorrect service/protocol names — check your application's documentation for the exact strings
• ▸Setting weight to 0 when you want load balancing (weight 0 means rarely used as backup)