SRV Record - Can't set port field to zero

[j3r]

I need to set an SRV record with a "Port" field of 0 (zero). This is allowed by the spec (RFC 2782), but not possible in the godaddy Domain Manager due to form validation not accepting a "Port" value that is less than 1.

Specifically, I'm setting DNS records to use fastmail for email on my domain using these values. This record pertains to IMAP client auto-discovery. By setting the "Target" field to a single period (.) and the "Port" field to zero (0), it essentially disables IMAP auto-discovery in favour of a separate record for IMAPS (I assume this from reading the spec, fastmail doesn't explain their logic here).

Any assistance or advice would be much appreciated 🙂

[j3r]

I should note that I can't set the "Target" field of the SRV record to a single period (.) either, which is also allowed by the spec.

[jonwalter · Accepted solution]

In the example below, SRV record Priority 1 and Weight 100 for SIP service with TLS protocol pointed to myserver.domain.tld will be added to the example.com domain.

1. Connect to the server over RDP or SSH

2. Execute the command below:

   # plesk bin dns --add example.com -srv '' -srv-service sip -srv-target-host myserver.domain.tld. -srv-protocol tls -srv-port 5060 -srv-priority 1 -srv-weight 100

3. To verify this command can be used

   # nslookup -type=SRV _sip._tls.example.com localhost

   
   Server: localhost
   Address: 127.0.0.1#53

   _sip._tls.example.com service = 1 100 5060 myserver.domain.tld.