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What is an SRV Record?

Emily Hall
Updated

What is an SRV Record?

SRV (Service) records are custom DNS records. They are used to establish connections between a service and a hostname. When an application needs to find the location of a specific service, it will search for a related SRV record. If it finds one, it will sift through the list of services and their connecting hostnames to find the following:

Creating an SRV record can potentially save you time later on.

For example, a compatible new email client will pull your ports and settings preferences from the SRV record if you have one configured. Without the SRV record, a new email client will guess (usually incorrectly) these preferences.

The SRV Structure

This section will walk you through the different parts of the SRV record.Screen-Shot-2017-07-03-at-9.37.44-AM.png

Service

Each SRV record begins with an underscore ( _ ). This lets the SRV record know where each line starts.underscore.png

The underscore is followed by the service name. Server services have symbolic names that are used in SRV records, like FTP (File Transfer Protocol) or IMAPS (Internet Message Access Protocol). This is the service you are publishing information for. For example, IMAPS would be an email service.Service.png

The Internet Assigned Numbers Authority (IANA) maintains a list of services and their symbolic names. Visit their list here.

After the service, a period ( . ) and an underscore ( _ ) are added to signify that the service has been established and the next section is beginning.Underscore-and-Period.png

Protocol

Protocol is listed next. This is usually TCP or UDP, two common transportation protocols.Protocol.png

If you would like more information about TCP and UDP, check out this article.

A period ( . ) follows the protocol. This signals that the protocol section has ended.period.png

Domain Name

Next, the service's domain name is listed.DomainName.png

A period is added at the end of the domain name to signify where it ends.domain-period.png

Priority

The priority number is added next. SRV records often list multiple services, so to establish which services should be looked at first, each line is given a priority number. The lower the number value, the earlier the SRV record will look at it.priority.png

For example, in the lines below, the first line has a priority of 10, while the second has a priority of 20. The line with the priority of 10 would be viewed first. The line with the priority of 20 would be viewed second.

_imaps._tcp.mydomain.com  10   1   993 username1.mail.pairserver.com

_imaps._tcp.mydomain.com  20   1   993 username2.mail.pairserver.com

Weight

If two or more services have the same priority, the weight number is used to determine which line should come first. The higher the number, the earlier the SRV record will look at it.Weight.png

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The numbering value is switched between priority and weight.

Priority: the lower the value, the more preferred.

Weight: the higher the value, the more preferred.

 

In the example below, the priorities are the same, but the weights differ. In this case, the line with the weight of 20 would be viewed first.

_imaps._tcp.mydomain.com SRV  20   10    993 username1.mail.pairserver.com

_imaps._tcp.mydomain.com SRV  20   20    993 username2.mail.pairserver.com

Port (optional)

The port number is optional. It is usually only included in lines related to email.

Port.png

Common port numbers are:

  • 993 (IMAPS)
  • 995 (POPS)
  • 587 (SMTPS)

Target

This is the name of the host provides the service.email.png

A period ( . ) is used to signal the end of the target.

end.png

If a hostname is absent, the service provider defaults to internal.

no-host.png

If the hostname is replaced by a period ( . ), the service will be blocked.

block.png

Setting Up an SRV Record 

Choose the tutorial that reflects your ACC interface type: 

Not sure what the difference is? See Which ACC Interface Am I Using? 

If you are using the Legacy Interface:

    1. Log into the Account Control Center (ACC) at my.pair.com
    2. Click Domains in the left sidebar
    3. Click Manage Your Domain Names
    4. In the “Domain Name” column, click the name of the domain name you would like to work on
    5. Click Manage Custom DNS Records
    6. Click Add New Custom DNS Records
    7. Next to Type of Record, select SRV from the drop down
    8. Click Proceed
    9. Next to Hostname, you may either enter a specific hostname or leave the field empty to create the SRV for the entire domain
    10. Next to SRV Record, input the SRV record

      tip-blue-35.png

      The SRV record structure:

      Hostname: _Service._protocol  
      SRV Record: Priority  Weight  Port(opt.) Target.

      Be sure to include the "." after the "Target."
    11. Once you have finished writing your SRV record, click Create SRV Record

Your SRV record is now complete.

If you are using the New ACC Interface:

  1. Log into the Account Control Center (ACC) at my.pair.com
  2. In the top navigation bar, click Domains
  3. Find the name of the domain that you would like to add the record to and click its Edit button
  4. In the “DNS” section, find Name Servers and click its Edit button
  5. Click the Manage DNS Records button
  6. Click the Add New DNS Entry button
  7. Next to Type of Record, select SRV from the drop down
  8. Click the Proceed button
  9. Fill out the the following information:

    Hostname Enter a specific hostname or leave the field empty to create the SRV record for the entire domain. 
    Priority Enter the SRV record’s priority in the textbox. See Priority. 
    Weight Enter the SRV record’s weight in the textbox. See Weight. 
    Port Enter the SRV record’s port in the textbox. See Port. 
    Target Enter the SRV record’s target in the textbox. See Target. 
  10. Once you have finished writing your SRV record, click the Create SRV Record button

Your SRV record is now complete.

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