this post was submitted on 22 Jun 2024
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A tool on Linux to scan for inboxes on other mailservers? (slrpnk.net)
submitted 4 months ago* (last edited 4 months ago) by boredsquirrel@slrpnk.net to c/linux@programming.dev
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I know this is basically a spam tool.

I think to know that you can query some info from a mailserver to test if an address exists.

I would like to find hidden addresses of some companies, for example I want to test if info@companyname.com exists.

Anyone know how to do that?

Update

I learned quite a bit

  • Mailserver block the requests that are used to get a list of inboxes ("accounts")
  • many servers will block mailservers that are not on an allowlist
  • many servers will block servers, if mails were sent to nonexistent addresses a couple of times
  • the message "recipient not known" will not appear often, as servers may "black hole" a senders mail and cut off the connection without sending the status message back
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[–] Shadow@lemmy.ca 2 points 4 months ago

This hasn't been possible for a long time. Mail servers do not typically reject a bad recipient immediately on the SMTP connection, they accept it and send a bounce email afterwards instead.