Guides - SRV Records

SRV Record Overview

An SRV (service) record provides the target hostname and port for a given service. This lets you direct traffic for specific services to a server other than what is specified in corresponding DNS records. SRV records are required for some protocols, such as XMPP and SIP.

Properties

• Service: The name of the service, such as sip or xmpp. The DNS Manager automatically includes a leading underscore character (_) and trailing period (.).

• Protocol: The name of the protocol you wish to use. Select from one of the supported protocols: tcp, udp, xmpp, tls, and smtp. The DNS Manager automatically formats this to conform to the SRV record standards.

• Domain: The name of the domain that will receive the original traffic for this service. This is generated automatically by Linode DNS Manager and is based on the root domain (the domain name specified when you created the Domain entry). If you wish to enable an SRV on a subdomain, you must create a separate zone (Domain entry) for that subdomain

• Priority: A number representing the priority of the target host, with lower numbers having higher priority. This value matters when you have more than one SRV record for the same service, allowing you to have one or more fallback hosts.

• Weight: A number representing the weight given to the target host. When multiple hosts have the same priority, clients should load balance them according to their weight. Hosts with larger weights are sent a larger portion of the traffic.

• Port: The port used by the service on the target host.

• Target: The target domain name where traffic should be redirected. This could be the root domain, a subdomain, or a separate domain entirely. Enter the @ character to use the root domain. The target domain name must have a valid A or AAAA record to specify the IP address of the target host.

• TTL (Time To Live): The length of time that DNS resolvers should store the DNS record before revalidating it with Linode’s name servers. Setting the TTL to 5 minutes is recommended for many use cases. If Default is selected, the TTL is set to 24 hours.