Helo command rejected: Host not found

Hey all,
I'm receiving the following error from one domain in particular and I'm trying to make sense of it.

Code:

Feb  3 13:22:33 www postfix/smtp/smtpd[25386]: NOQUEUE: reject: RCPT from mail.xxxxx.ca[142.239.xxx.xx]: 450 4.7.1 <barracuda.xxxxx.ca>: Helo command rejected: Host not found; from=<[email protected]> to=<[email protected]> proto=ESMTP helo=<barracuda.xxxxx.ca>

when it says "Host not found" does that mean mail.xxxxx.ca is trying to use my server to send an email but my server does not recognize the host name?

 

Yes.
More info from Internet Search Engines with

Code:

postfix "host not found"

 

What exactly does the "Helo command rejected" mean. am I able to allow these emails? is that what the global postfix whitelist does?

 

Do you want to receive e-mails from that sender? Mostly these misconfigured e-mail servers send spam.

 

Apparently it was an issue on my clients server. Thanks folks.

 

Is there anyway to white list misconfigured senders, I have tried to whitelist with value 10 with ISPConfig, but still get this error:

NOQUEUE: reject: RCPT from mail.uxxxxxxxx.com[xxx.xxx.51.167]: 450 4.7.1 <MAIL02.uxxxxxm.com>: Helo command rejected: Host not found;

To get there ISP to fix the problem seems an issue , so was hoping @xxxxx.com domain whitelisting would work , but doesn't seem to , any other way to whitelist that I am missing ?

 

You can use "check_helo_access" in the smtpd_helo_restrictions to work around this. For more information take a look in the docs https://www.postfix.org/postconf.5.html#check_helo_access

 

Thanks guys, was hoping for the impossible I guess , had to disable globally to get to temporary solution