opening a telnet/smtp connection without waiting for response

DeLos has asked for the wisdom of the Perl Monks concerning the following question:

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Re: opening a telnet/smtp connection without waiting for response by K_M_McMahon (Hermit) on May 18, 2005 at 22:17 UTC
Hate to copy from merlyn, but I'll refer to "freak" and recent threads Recent Posts from DeLos could have a good reasoning. And in one post it seemed as if he wanted to test a spam filter, this could be for the good guys or the bad guys. I don't know, but I thought I would point out the trend. opening a telnet/smtp connection without waiting for response Multiple Ip for smtp connection Re: Spoofing an IP using perl? -Kevin `my $a='62696c6c77667269656e6440676d61696c2e636f6d'; while ($a=~m/(^.{2})/s) {print unpack('A',pack('H*',"$1"));$a=~s/^.{2}//s;}` [download]	[reply] [d/l]
Re: opening a telnet/smtp connection without waiting for response by redhotpenguin (Deacon) on May 18, 2005 at 22:07 UTC
By bypassing this, you may trigger spam filters that look for clients which are known as earlytalkers. I run Qpsmtpd which has a plugin called check_earlytalker, and closes the connection if the client talks early.	[reply]
Re: opening a telnet/smtp connection without waiting for response by dave0 (Friar) on May 19, 2005 at 13:53 UTC
I'm not sure what you think you're going to accomplish by sending a MAIL FROM: before the connect banner arrives. Before sending a MAIL FROM, you generally need to: receive the connect banner send a HELO or EHLO receive a successful (2xx) response to the HELO/EHLO command Otherwise, most SMTP servers will consider you to be either a broken client (and just disconnect) or a spammer (and take whatever measures they deem appropriate, such as blacklisting you, reporting your IP to an RBL maintainer, etc). I suppose if you're testing a filtering product, sending MAIL FROM immediately does make sense. In that case you probably want to throw as much test data, both RFC-conformant and non-conformant, as you can think of. The place for you to start looking is IO::Socket::INET. Once you've generated your socket, do something like `$sock->send("MAIL FROM:<spammer@somedomain.tld>")`, and call $sock->recv to get your result. You might also want to look at the guts of Net::SMTP to get some ideas.	[reply] [d/l]
Re^2: opening a telnet/smtp connection without waiting for response by DeLos (Acolyte) on May 25, 2005 at 15:40 UTC
I know my questions keep lookign suspect, but that truly is because I am testing spam related software. I can give you the company (openwave.com) but that is probably it. Yes the sending information before the banner should trigger some action by the server. In much the way if you pipe a file to telnet. I will try the Socket::INET and report my findings. Most of the problems I have been having is that all these modules need info back from the server before they are considered "open".	[reply]
Re^3: opening a telnet/smtp connection without waiting for response by DeLos (Acolyte) on May 25, 2005 at 18:20 UTC
bah, mundane details. Here I was digging deep for a problem on the surface. out SMTP fucntion explicitly waits for a return from the server, this is not in the Telnet object. So that was my problem. Oh well. Thanks guys!	[reply]