SRV Record Lookup Tool
SRV Lookup is a diagnostic tool used to locate the specific port and hostname for network services such as VoIP, Minecraft servers, or LDAP directories.
Discover the hosting details for any network service. Analyze priority, weight, port, and target parameters for seamless service delivery.
Type a domain to check DNS records.
What is a DNS SRV (Service) Record?
A SRV (Service) record is a specialized type of DNS record that identifies the location (hostname and port number) of specific services on a network. While standard A records only map a domain to an IP, SRV records allow applications to discover where a service—like VoIP, instant messaging, or a game server—is hosted and on which port it is listening.
Defined in RFC 2782, the SRV record introduced a standardized way for "Service Discovery" without hardcoding port numbers into applications. This makes it possible to host multiple services on the same server or across different servers while allowing clients to find them automatically using only the domain name.
Anatomy of an SRV Record
An SRV query usually follows a specific underscore-prefixed format:
Example: _minecraft._tcp.example.com
Service: The symbolic name of the service (e.g., sip, ldap, minecraft).
Protocol: The transport protocol, usually _tcp or _udp.
Name: The domain name for which this record is valid.
Priority vs. Weight: Traffic Control
Priority (Failover)
Similar to MX records, the lowest priority value is attempted first. If the server with priority 10 fails, the client moves to 20. This allows you to set up primary and backup nodes for your services.
Weight (Load Balancing)
For records with the same priority, the weight determines the relative amount of traffic. A record with weight 60 will receive three times as much traffic as one with weight 20. This enables graceful load distribution.
Common Use Cases for SRV Records
Minecraft Game Servers
SRV records allow players to connect to play.example.com without typing the port number, even if the server is running on a non-standard port like 25566.
VoIP / SIP Discovery
Used by IP phones and softclients to find the SIP gateway and proxy servers responsible for call routing on a domain. This works alongside MX records for full email/voice setup.
Active Directory / LDAP
Windows clients use SRV records to find Domain Controllers. Verify your internal nameservers are responding correctly to these queries.
Frequently Asked Questions
Why do SRV records use underscores (_)?
Underscores are used to prevent name space collisions with actual hostnames. By prefixing the service and protocol (e.g., _sip._tcp), the DNS system ensures that these records don't get confused with normal subdomains or A records.
Can I use an IP address as an SRV target?
No. According to RFC 2782, the target field of an SRV record must be a hostname that points to an A or AAAA record. It cannot be an IP address directly.
What is a "Zero SRV" record?
A target of "." (a single dot) in an SRV record is used to indicate that the service is decidedly not available at this domain. This is an official way to "opt-out" of a service discovery protocol.
Does SRV help with SEO?
SRV records are technical infrastructure records and do not directly impact search engine rankings. However, they ensure proper service availability for your users, which indirectly affects user experience and site reliability.
Common Troubleshooting Tips
- Ensure the target domain exists and has an A record.
- Check if the protocol (TCP/UDP) matches your application requirements.
- Verify that your firewall allows traffic on the port specified in the SRV record.
- DNS propagation for SRV records follows the same 24-48 hour rule as other records.