What Are SRV Records
An SRV record is a DNS record that tells clients which host and which port run a named service, and which server to try first. One line reads _sip._tcp.example.com. 3600 IN SRV 10 60 5060 sipserver.example.com. The target must resolve to an A or AAAA record, not a CNAME.
For admins wiring SIP phones, Teams federation or a game server: the six fields, real record values, and the two commands that prove they answer.
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- 6
- Updated
- 14 Nov 2026
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- WebJi® team
Last editorial update: 15 November 2026.
What is an SRV record?
An SRV record is a DNS record that publishes the host and port where a named service runs, plus a priority and weight clients use to choose between servers. It is written as _service._proto.name and carries DNS record type 33. Where an A record answers "which IP", an SRV record answers "which host, which port, and which one first" — the only common record that carries a port number.
| Field | Example | What it means |
|---|---|---|
| Name | _sip._tcp.example.com. | service and transport, then the domain |
| TTL | 3600 | seconds a resolver may cache the answer |
| Class and type | IN SRV | always these two words |
| Priority | 10 | lower is tried first |
| Weight | 60 | share of traffic among equal priorities |
| Port | 5060 | where the service listens on the target |
| Target | sipserver.example.com. | hostname with an A or AAAA record |
Assembled, the line reads _sip._tcp.example.com. 3600 IN SRV 10 60 5060 sipserver.example.com. The trailing dots matter in a zone file; a control panel adds them for you. Where this record sits among A, MX, TXT and the rest is mapped in DNS records explained.
How do priority, weight, port and target work together?
Priority is the first decision and weight the second: clients sort answers by priority, try the lowest number first, and use weight to split traffic across records that share a priority. Only when an entire priority group fails does the client fall back to the next number up.
| Target | Priority | Weight | Role |
|---|---|---|---|
| bigbox.example.com | 10 | 60 | main server — 60% of new sessions |
| smallbox1.example.com | 10 | 20 | second choice — 20% |
| smallbox2.example.com | 10 | 20 | third choice — 20% |
| backupbox.example.com | 20 | 0 | used only when all three above fail |
The three priority-10 records share 100 weight points, so new sessions land 60/20/20 across them; the priority-20 box sits idle until the whole group stops answering. The port can differ per record — that is how one domain runs SIP signalling on 5060 and TLS on 5061 simultaneously. The target must resolve to an A or AAAA record; pointing it at a CNAME is invalid, and clients may silently ignore the record.
Which services actually use SRV records?
SRV records serve protocols that need a port and a preference order — real-time communication, directory lookups and game servers chiefly. A plain website needs none; no browser looks for an SRV record to open a page.
| Service | Record name | Usual port |
|---|---|---|
| SIP telephony | _sip._tcp / _sip._udp | 5060 |
| Microsoft Teams federation | _sipfederationtls._tcp | 5061 |
| XMPP chat | _xmpp-client._tcp | 5222 |
| Active Directory | _ldap._tcp.dc._msdcs | 389 |
| Mail submission | _submission._tcp | 587 |
| Minecraft (Java Edition) | _minecraft._tcp | 25565 |
Two of these come up constantly in tickets. Microsoft's own external DNS reference gives the Teams federation record as priority 100, weight 1, port 5061, target sipfed.online.lync.com — the record that lets a domain exchange instant messages with external organisations. And Minecraft's Java Edition client resolves _minecraft._tcp so a server can live on a non-default port behind a clean domain name; the Bedrock Edition client does no SRV lookup at all, so the same trick fails there by design.
How do you add an SRV record in cPanel?
In cPanel the SRV record is added in the Zone Editor, not in the email section, and the domain must use the hosting account's name servers. If the domain's DNS sits at the registrar, edit the record there instead — with the same six fields.
- Open Zone Editor: cPanel → Zone Editor → Manage next to the domain.
- Add the record: click Add Record and choose SRV from the type list.
- Name: type the service and transport, e.g.
_sip._tcp— the panel appends the domain; check the preview line. - Values: TTL 3600, Priority 10, Weight 60, Port 5060 (or the values your service published).
- Target: the server hostname, e.g. sipserver.example.com — it must already have an A record.
- Save and wait out the TTL before testing in a client.
That panel is part of cPanel hosting; domains registered through domain registration can point their name servers at the same account so the record and the domain live in one place.
How do you check an SRV record with dig or nslookup?
Two commands cover every desktop: dig +short SRV _sip._tcp.example.com returns four values — priority, weight, port and target — and Windows nslookup does the same after set type=SRV. Run them from a terminal, not from the panel's preview.
- macOS/Linux:
dig +short SRV _sip._tcp.example.com - Windows: run
nslookup, thenset type=SRV, then_sip._tcp.example.com - Read the answer: it must show the same four values you entered, e.g.
10 60 5060 sipserver.example.com.
An empty answer means one of four causes: the target is a CNAME, the name lost its underscores, the port was left at 0, or the previous answer is still cached for the length of the old TTL. If the record looks right and still does not answer, email support@webji.services with the domain, the record name and the command output; more DNS debugging screens are in how to check DNS records.
How is an SRV record different from MX, A and CNAME?
Each record answers a different question, and mixing them up is why some SRV edits never work — SRV is the only one of the four that carries a port.
- A / AAAA: this name is this IPv4/IPv6 address. Nothing about services or ports.
- CNAME: this name is an alias of that name — fine for websites, invalid as an SRV target.
- MX: mail for this domain goes to that host, with a preference number and no port. What an MX record is covers it fully.
- SRV: this service runs on that host and port, tried in this order. The CNAME guide and what DNS is fill in the rest of the map.
An SRV record does not serve web traffic and does not make a site faster — name servers and resolution only decide where a request goes, never how fast the page behind it renders.
Frequently asked questions
What is an SRV record used for?
It tells a client which host and port run a named service, and which server to try first. SIP phones, Teams federation, XMPP chat, Active Directory, mail-submission clients and Java Edition Minecraft servers use it. A website does not need one.
What do priority and weight mean in an SRV record?
Priority sorts records: the lowest number is tried first and higher numbers stand by as backups. Weight splits traffic between records sharing a priority — weights of 60, 20 and 20 send 60, 20 and 20 percent of new sessions to those three hosts.
How do I add an SRV record in cPanel?
Open Zone Editor, click Manage next to the domain, then Add Record and choose SRV. Enter the service name such as _sip._tcp, a TTL of 3600, priority, weight, port and target hostname, then save. The domain must use the hosting name servers for the edit to matter.
Does Microsoft 365 need SRV records?
Not for ordinary mail — an Autodiscover CNAME, MX and SPF TXT do that work. The SRV record Microsoft documents for Teams-only tenants is _sipfederationtls._tcp with priority 100, weight 1, port 5061, pointing at sipfed.online.lync.com, which enables external federation. Add exactly the records your tenant's admin centre lists, no more.
Why is my SRV record not working?
Four causes cover most cases: the target is a CNAME instead of an A record, the name is missing its underscores, the port is still 0, or the old answer is cached for the previous TTL. Run dig +short SRV on the exact name and compare the four values against what you entered.
Last editorial update: 15 November 2026.
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