From owner-freebsd-questions@FreeBSD.ORG Mon Oct 5 17:59:26 2009 Return-Path: Delivered-To: freebsd-questions@FreeBSD.ORG Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id D89CD106566B for ; Mon, 5 Oct 2009 17:59:26 +0000 (UTC) (envelope-from wmoran@potentialtech.com) Received: from mail.potentialtech.com (internet.potentialtech.com [66.167.251.6]) by mx1.freebsd.org (Postfix) with ESMTP id A85DE8FC13 for ; Mon, 5 Oct 2009 17:59:26 +0000 (UTC) Received: from localhost (pr40.pitbpa0.pub.collaborativefusion.com [206.210.89.202]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mail.potentialtech.com (Postfix) with ESMTPSA id 715C3EBC0A; Mon, 5 Oct 2009 13:59:25 -0400 (EDT) Date: Mon, 5 Oct 2009 13:59:24 -0400 From: Bill Moran To: Gary Kline Message-Id: <20091005135924.be749247.wmoran@potentialtech.com> In-Reply-To: <20091005173717.GA44563@thought.org> References: <20091005173717.GA44563@thought.org> Organization: Bill Moran X-Mailer: Sylpheed 2.7.1 (GTK+ 2.16.5; i386-portbld-freebsd7.2) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: FreeBSD Mailing List Subject: Re: way to check an email without sending it?? X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 05 Oct 2009 17:59:26 -0000 In response to Gary Kline : > > Hey Guys, > > Is there a way I can tell that an email address, say > > joe@foo.com > > is still valid without joe knowing that I am curious? --And, > yes, this isn't a FBSD-specific question... . > > thanks for any insights, Sure. Telnet to the service and start a SMTP transaction, but then abort it: $ telnet mail.potentialtech.com 25 Trying 66.167.251.6... Connected to mail.potentialtech.com. Escape character is '^]'. 220 mail.potentialtech.com ESMTP If you spam me I will bounce you helo mail.potentialtech.com 250 mail.potentialtech.com mail from: 250 2.1.0 Ok rcpt to: 450 5.7.0 : Recipient address rejected: User unknown in local recipient table quit 221 2.0.0 Bye Connection closed by foreign host. If you don't get a rejection after the "rcpt to:" line, then you know the server will accept the mail and you can close the connection without completing the transaction. Note, that this is no guarantee. Some spam catching nonsense may accept the mail right up to end, then throw it away without delivering it. -- Bill Moran http://www.potentialtech.com http://people.collaborativefusion.com/~wmoran/