5.1.2 - Bad destination host 'DNS Hard Error looking up - what does this mean?

Posted on 2007-11-26
Medium Priority
Last Modified: 2012-05-05
Just received message back from bounce and it states that a completely valid account on our domain can not be delivered mail. Message reads:

5.1.2 - Bad destination host 'DNS Hard Error looking up....
Question by:ricec

Accepted Solution

mdcsea earned 2000 total points
ID: 20352129
This is a pretty straightforward error indicating that there was an MX lookup error.  What is the rest of the error message (include the specific domain, not a placeholder)?  Have you checked the DNS for your domain to make sure all is well?  Do a DNSreport here:  http://www.dnsstuff.com/   What are you using for a spam filter?  Some spam relay services can cause this issue.

Author Comment

ID: 20353673
this came back as an error for just one address of a multi contact communication send out. The error message said that the address name.secondname@domain.com - DNS had an issue looking this up. I check ed DNS and all was ok. I will do the DNSreport from this site thanks and let you know. Also we are using Ironport as a Spam Filter app.

Expert Comment

ID: 20805690
Forced accept.

EE Admin
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Expert Comment

by:S Connelly
ID: 24543815
These forced accepts are sure annoying.

I came here hoping to find further information but this question may not even have been resolved. This is a misleading "Accepted Solution". Seriously, isn't it better to simply delete the question or ask the rest of the community for their opinion?

Anyhow, if anyone reads this, this error may also occur when your ISP has flagged your account as a sender of SPAM. This error occurs when sending out emails with a large number of recipients.

I'm still trying to determine whether or not this is the case with one of my clients.
LVL 51

Expert Comment

by:Keith Alabaster
ID: 24543909
Thanks for your comment - I read all the comments that are added or posted to questions that I have either worked on myself or have been involved with in my 'Official' hat on.

In this particular case, no, it was not erroneous back in 2007. the dns reports available from DNSSTUFF were likely the most efficient, most informative source of information and places to look for your DNS issues on the planet. As they were free they were used a great deal and identified almost any error you could think of AND gave great guidance on resolutions of such errors.

I believe they are still available but these days it is a chargeable service and so i do not - personally - use it anymore and so do not know the form of those services.


Expert Comment

by:S Connelly
ID: 24544045
Hi Keith, I was speaking more in general terms about forced accepts and in particular cases where the answer may not be correct or complete. There are better (or worse) examples on EE than this one.

My earlier comment was solely based upon what my client told me. Apparently their ISP support representative said this.

Anyhow, I finally received an email with the error message. It took me a few seconds to see that my client made the mistake. The error message stated, <'suffix@domain'>. It seems clear to me that the email address incorrectly included ' in it. That's ' ' ' ' ' ' ' ' '  <-- symbol is either quotes or apostrophes.
LVL 51

Expert Comment

by:Keith Alabaster
ID: 24547356
lol - OK, no problem.

To be frank, that is a plus and a minus of the site. On one hand (no conceit intended) you can get old hands who have done nothing but this job (in IT for 30+ years) like myself and many others and you also have the new, young and still disgustingly enthusiastic 'tryer'. They learn though by keeping on the forums and provide better responses - and learn more - as they go. Not often, but once or twice, I have still learnt the odd new-trick that I wasn't aware of.

Anyway, hopefully we will see you again here in the future - if you need help that is....



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