Why do I get message has exceeded maximum number of hops?

Question

Sending a message to someone at your mail server causes the mail server to become busy for a few seconds and then the message is returned with:

This mail message has exceeded the maximum number of hops.
The requested destination was:
   user@192.168.0.39

or some other address where the part after the “@” is an alias of the local domain name.

Answer

This is typical of any mail server that has not been configured correctly. This occurs when the domain name resolves to the mail server’s address but the mail server does not recognise the domain as one it is running.

Some specific cases where problems can occur include:

• The post service then tries to send the message out again, only for it to be delivered back to the local SMTP service. It goes round in this manner until the hop count is reached.

  To resolve the problem, log on to the GMS Mail interface, select "Domain" and click on the appropriate domain in the domain selector tree. Enter the IP address or new domain name in the alias listing. When you press update, the problem will be resolved.

  Note: RFC822 strongly recommends that you do not use the native IP address of your mail machine in email addresses. In addition, if you must, the IP address must be enclosed in square brackets:

      [192.168.0.39]
  

• Another way this error can occur is where the MX record is pointing back round to itself, i.e. both your second and third level MX records point to the same machine, but address it differently, this could indeed result in the behaviour you are seeing. Also please note that the use of CNAME records in MX is not recommended. MX should use an A record.

See Also:

• Why am I getting an “Exceeded Hop count” failure email?

Keywords:hops too many bounce looping MX CNAME relay firewall records