# SRV record

Canonical: https://inetgeek.com/dns/srv-record/

An SRV record publishes where a particular service runs — including its port, which no other record type carries.

## What an SRV record carries

An SRV record, defined in RFC 2782, names the host and port for a specific service. It is the only common record type that includes a port number, which is why protocols that do not use a fixed port rely on it.
The record name encodes the service and protocol as underscore-prefixed labels: _sip._tcp.example.com. The underscores prevent collisions with real hostnames.

## What an SRV record looks like

The value carries four fields in a fixed order — priority, weight, port, target: _sip._tcp.example.com. 3600 IN SRV 10 60 5060 sipserver.example.com.
Here the client should try sipserver.example.com on port 5060, at priority 10 and weight 60. The target is a hostname needing its own address record, and a single dot in that position means the service is explicitly not offered.
Because the name itself is part of the lookup, an SRV query for a wrongly assembled name fails quietly rather than loudly. The answer is an ordinary empty one, indistinguishable from a service that was simply never published.

## Priority and weight

Each record carries a priority and a weight. Priority works like MX: lower numbers are tried first. Weight distributes traffic among records that share a priority, in proportion to the weight values.
A client is expected to honour both. This gives finer control than MX records, which have priority but no weight.

(Interactive explainer on the canonical page — nothing to check live, this is reference text.)

## Where you will meet it

SRV records are used by SIP, XMPP, Minecraft servers, Microsoft Active Directory and various autoconfiguration mechanisms.
Email does not use SRV for delivery — that is what MX is for. Some mail clients do use SRV records to discover submission and IMAP settings automatically, which is a different job.

## Related records

- [MX record](https://inetgeek.com/dns/mx-record/): Names the mail servers that receive email for a domain.
- [A record](https://inetgeek.com/dns/a-record/): Maps a hostname to an IPv4 address.
- [TXT record](https://inetgeek.com/dns/txt-record/): Holds arbitrary text, used for verification and email policy.