SMTP Catch-all detection Response 5.7.1 Service unavailable

[liuyihan]

I have deployed this project locally and am conducting SMTP catch-all monitoring, but I encountered an error message: "5.7.1 Service unavailable, Client host [xxx] blocked using Spamhaus." How can I prevent this issue from occurring?

[NexaVerse-AI]

Try using proxy networks for rotating IP address, however with that you will encounter another issue - that some email services require PTR records for sender.

This can be manageable with using micro servers for those hosts.

[liuyihan]

micro servers

How to use micro servers, can give me an example? @NexaVerse-AI

[NexaVerse-AI]

Setup small servers, setup PTR and other email config, best approach would be to run postfix or similar so you have valid mail records for your domain.

Then you can run SMTP verification.

You would need several small servers to accomplish and also prevent rate limit, and blacklisting by Spamhaus.
Rotate the IP of your server say every X verifications to be sure you are able to maintain clean IP.

[ashik-rafat-reea]

@NexaVerse-AI can you provide some tutorial how to implement this? The proxy server i have used, all have blocked 25, 465 and 587 port