On 2006-04-03, at 0824, Robin Bowes wrote:
Rick Widmer wrote:

I was under the impression your interest is based on Robin Bowes
suggestion about the validrcptto.cdb patch, so it is "does this mailbox exist." We may as well make it easy, it should be a popular function.

Yes - having this functionality would obviate the need to maintain the
validrcptto list. Any tool that wants to check the existence of a
mailbox for a given email address on a given host would just need to
telnet to port 89 and supply a command like "exists [EMAIL PROTECTED]".

the problem is that validrcptto.cdb doesn't check "mailboxes"- it checks "recipient email addresses". mailboxes are recipients, yes, but other things can be valid recipients as well- aliases, certain flavours of "anything" (in case of a ".qmail-[something-]default" file or a domain with a non-bounce "catch-all" setting), and some people have custom requirements where they want to control which addresses can receive mail from outside.

An "OK" responose would mean it does exist. It should not quite
automatically to allow the checking of several addresses in sequence, e.g:


this is known as a "dictionary attack" (or a "bad thing".) it allows the attacker to enumerate which email addresses do and don't work on your server. this used to be a major strategy of the wily spammer, but most mail servers now take steps to prevent it. however, i have seen a few people try it on my own server (and promptly blacklisted those IP addresses.)

Does vpopmaild fork? i.e. Does it allow multiple connections? I guess it
uses tcpserver to run it so tcpserver will do all the work. Cool.

that's it exactly- tcpserver handles all of the networking stuff, vpopmaild is just talking to stdin/stdout, with log output going to stderr. makes it really easy to write server programs.

| John M. Simpson - KG4ZOW - Programmer At Large |
| http://www.jms1.net/           <[EMAIL PROTECTED]> |
| Mac OS X proves that it's easier to make UNIX  |
| pretty than it is to make Windows secure.      |

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