Free tool
Find the host and port for a domain's services, with priority and weight.
Enter the full service name, such as _sip._tls.example.com or _xmpp-server._tcp.example.com, not just the domain.
An SRV (Service) record specifies where a particular service runs: its hostname, port, priority, and weight. Protocols such as SIP, XMPP and LDAP use SRV records for service discovery, and Outlook can find Autodiscover through one.
SRV names follow the pattern _service._protocol.domain. This tool resolves the SRV record for whatever name you enter and lists each target with its port.
The format is _service._proto.name TTL IN SRV priority weight port target. For example:
_sip._tls.example.com. 3600 IN SRV 10 60 5061 sip1.example.com.
_sip._tls.example.com. 3600 IN SRV 10 40 5061 sip2.example.com.
_sip._tls.example.com. 3600 IN SRV 20 0 5061 sip-backup.example.com.
_xmpp-server._tcp.example.com. 3600 IN SRV 5 0 5269 xmpp.example.com.
The two underscore labels name the service and the protocol. A client looking for SIP over TLS takes the lowest priority first, so it uses sip1 and sip2, splitting connections by weight: about 60% to sip1 and 40% to sip2. sip-backup, at priority 20, is only tried if neither answers. Each line also gives the port to connect to: 5061 for the SIP servers, 5269 for XMPP.
As with MX, the target must be a hostname with its own A or AAAA record. RFC 2782 does not allow an IP address or an alias there.
Enter the full service name, not just the domain: example.com on its own has no SRV records, because they only exist at the underscore names. The table shows Priority, Weight, Port and Target for every record, sorted by priority with the lowest first, and the bar above gives the record count and query time.
Queries go live from the PulseStack™ server in the UK to Google Public DNS (8.8.8.8), with Cloudflare (1.1.1.1) as the fallback, and nothing is stored. Read the table the way a client does: lowest priority first, traffic shared by weight among equal priorities, and higher numbers kept as backups.
No SRV records found means nothing is published at that exact name. Check the labels your software expects, including the leading underscores and the protocol: _sip._tcp and _sip._tls are different names.
Names you are likely to meet: _sip._tls and _sipfederationtls._tcp for SIP and older Microsoft Lync and Skype for Business setups, _xmpp-client._tcp and _xmpp-server._tcp for XMPP chat, _ldap._tcp for directory services, _autodiscover._tcp for Outlook, _minecraft._tcp for Minecraft Java servers, and _caldavs._tcp or _carddavs._tcp for calendars and contacts.
The domain added twice. Many DNS panels add your domain to whatever you type in the name field, so entering the full name creates _sip._tls.example.com.example.com. If your panel works that way, type only _sip._tls, then check the result here.
Values in the wrong boxes. Some panels have separate boxes for service, protocol, priority, weight, port and target, while others take one line of text. A port typed into the weight box gives a record that looks valid and points nowhere useful.
The right record, but a closed port. DNS can be perfect while nothing listens on the port. A PulseStack™ port monitor on a paid plan connects to a host and port from London, New York and Sydney and alerts you when it stops accepting connections.
On macOS or Linux, run dig SRV _sip._tls.example.com +short. On Windows, use nslookup -type=SRV _xmpp-server._tcp.example.com, or in PowerShell Resolve-DnsName -Name _ldap._tcp.example.com -Type SRV.
dig prints the four values in the same order as the table: priority, weight, port, target. To check that a target resolves, look it up with the A record lookup, and for the domain's other records use the DNS lookup.
Enter the full SRV name, which follows the format _service._protocol.example.com, for example _sip._tls.example.com. Unlike A or MX records, SRV records live at these underscore-prefixed names.
Priority works like MX: lower is tried first. Weight distributes load among records of equal priority, so a record with weight 20 receives roughly twice the traffic of one with weight 10.
Common users include SIP and VoIP, XMPP chat, LDAP and Active Directory, Minecraft Java servers, and Outlook's Autodiscover. If a protocol supports SRV-based discovery, clients can find the service without a hard-coded host and port.
It means the service is deliberately not offered at that domain (RFC 2782). Clients that find it stop looking, instead of trying other ways to reach the service.
Every one runs a real check, live, with nothing to install.
An SRV record only says where a service should be. PulseStack™ port monitors connect to the host and port from London, New York and Sydney and alert you when it stops accepting connections. Included from the Starter plan at £9 a month, with a 14-day trial and no card.