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SRV Record Lookup — service location in DNS for SIP, Teams, LDAP, XMPP and more.

Query SRV (Service) records against authoritative DNS. SRV publishes the host and port for a specific service in DNS so clients don't have to hard-code it — used by SIP trunking, XMPP federation, Microsoft Autodiscover, Active Directory service location, Matrix homeserver federation, Minecraft, and dozens of other protocols. Returns priority, weight, port, and target, with target-resolution verification.

01 · TRY IT

Look up an SRV record

SRV names follow the format `_service._proto.host`. Both parts start with an underscore.

02 · WHAT IT RETURNS

What the SRV lookup shows

Priority ordering (Fallback chain)

Lower priority = tried first. Same priority = round-robin via weight. Standard MX-style fallback semantics.

Weight for load balancing (Within priority)

Distributes load among same-priority entries. `10 60 5060 sip1` + `10 40 5060 sip2` = 60/40 traffic split within priority tier 10.

Port + target (Where clients connect)

Target is the hostname to connect to on the given port. Target must resolve to A/AAAA — CNAMEs are forbidden per RFC 2782.

Target resolution check (End-to-end)

This tool follows the target to confirm it resolves to A/AAAA. Broken targets are flagged — a common cause of service-discovery failures.

Service class recognised (AI verdict)

Common SRV service names recognised — SIP, XMPP, Autodiscover, LDAP, Kerberos, Matrix, Minecraft — with brief context on what the service expects.

Multi-record ordering (Client visibility)

Priority-then-weight order shown so you can see exactly how a well-behaved client will iterate the answer set.

03 · WHY IT MATTERS

When to check SRV

  • Microsoft 365 / Exchange Autodiscover Outlook, mobile mail apps, and Exchange clients use `_autodiscover._tcp.<domain>` to find the Exchange endpoint. Missing or wrong SRV = users can't add accounts.
  • SIP trunk provisioning VoIP providers publish `_sip._udp` or `_sip._tcp` SRV to point clients at the SIP proxy. Wrong port or target = calls fail silently.
  • Active Directory service location Domain controllers publish `_ldap._tcp`, `_kerberos._tcp`, `_gc._tcp` SRV records. Broken SRV = domain-joined machines can't authenticate.
  • Matrix homeserver federation If your Matrix server runs on a non-standard port, `_matrix._tcp.<domain>` is the only way to be federation-discoverable.
  • XMPP / Jabber federation `_xmpp-server._tcp.<domain>` publishes the federation endpoint. Missing SRV = other XMPP servers can't reach you.
04 · QUESTIONS

Common questions

  • What is an SRV record? A DNS record that publishes the host and port for a specific service, so clients don't have to hard-code endpoints. Format: priority + weight + port + target. Used by SIP, XMPP, Autodiscover, LDAP, Kerberos, Matrix, and many other services.
  • How is SRV different from MX? MX is email-specific. SRV is generic — any service can publish its endpoint the same way. If MX were invented today it would be an SRV record. SRV adds a `weight` field for finer load-balancing.
  • What does the weight field do? Balances load among same-priority records. Weights are relative — `10` + `10` = 50/50, `70` + `30` = 70/30. Clients pick weighted-randomly within the same priority tier.
  • Can SRV point to an IP? No — the target must be a hostname that resolves to A/AAAA. Bare IPs are invalid, and CNAME targets are prohibited per RFC 2782.
  • What if two SRV have the same priority and weight? Clients pick randomly with equal probability. Effectively round-robin with no bias.
05 · RELATED

Related tools

Open Port Scanner (Reachability)

Verify the target on the SRV-advertised port actually accepts connections.

MX Record Lookup (Email SRV)

MX is the email-specific ancestor of SRV.

TLSA (DANE) Lookup (Cert pinning)

SRV + TLSA is the pattern for authenticated service discovery (e.g., SMTP DANE).

DNS Query (All Records) (Super tool)

Full DNS dump.