Why is this in my Postfix log?

I’m suddenly getting entries like this in my Postfix log. Can anyone tell me what they are and why they have suddenly appeared? Are these IP addresses or Reverse IP?

   1 RBL lookup error: Host or d...
     1 RBL lookup error: Host or do...
     1 RBL lookup error: Host or do...
     1 RBL lookup error: Host or dom...
     1 RBL lookup error: Host or dom...
     1 RBL lookup error: Host or dom...


A google search found this:-

It looks like there may be an issue with the blacklist server(s).

I also found this site:-


Which reports:-

“LashBack may change or discontinue the databases, or their availability to you, at any time without notice.”

I only mention this, as recently seen this with the zen spamhaus rbl; where they were actively blocking lookups.

Regards Tom.

When using publicly available DNS Servers like Google, etc, a lot of the RBL’s restrict the lookups, Spamhaus being one of them. Usually, using your ISP DNS Servers, or for example running your own DNS Server that then queries Google or other public DNS servers would get around this problem. Since Spamhaus, would then see either your ISP’s DNS Servers making the query, or your DNS server which uses your public IP making the queries, instead of the public available ones.

I got the same here.
In this specific case, it has nothing to do with that restriction, but it just happens that unsubscore.com has
discontinued its service. So:

Just remove the following line from your /etc/postfix/main.cf and reload your postfix.

reject_rbl_client ubl.unsubscore.com,


Yes, I think you are correct. I blocked ALL Stretchoid’s scanners along with binary edge ninja and Shodan scanners and as soon as I did those I started getting those messages. Coincidence? Unless they have shut up shop for EVERYONE, I doubt it and yes, my tinfoil hat fits just fine!