Hello Folks,

This is Nadeem Ahmed, I get an error message, cannot deliver email to 557. Your domain does not have a valid DNS MX record. Disconnecting...If somebody in the forum could explain to me about this and what does 557 number denote, I would be very thankful.

Regards,

Nadeem Ahmed.

Hello Roberto,

Thank you very much for the response.

Just wanted to know that what do I have to do in order to resolve this.

Thanks,

Nadeem Ahmed.

Hi Nadeem,

Let me jump in... maybe I can help.  Here's how you can find out if the sender's domain has a valid MX record..

• Go to http://www.dnsstuff.com/
• In the top-right box, called DNS lookup, type in the sender's domain; from the drop-down box, choose "MX"
• Click the button and see the results.

If you get a message like this, then they do not have an MX record:

No MX records exist for sender-domain.com

Otherwise, you'll get a list of their MX entriy(ies).


Also, it's helpful to know why SpamFilter allows you to block email from domains without MX records (btw, that setting can be turned off).

Should anyone try to send a message to, say, mydomain.com, the first thing their smtp server does is a lookup for MX record(s) for mydomain.com.  The results give the sending server the means to determine where (what i.p.) the message can be sent to.  If no MX results are returned, the sending server may a.) guess or b.) give up. 

It's a poor configuration when a domain that sends email doesn't have a MX record.  It makes sending email to the domain troublesome; it also makes them look suspiciously like spammers - after all, spammers are probably the people solely concerned with sending email and not worried about being able to receive it.

Stephen