On Wed, Feb 07, 2007 at 06:25:41PM -0800, Mike Lyon wrote:

Their gateway is blocking mail from my host. Of course, there is no clueful contact info on their webpage...

I know you asked for off-list, but since this (mail to Verizon refused) is a recurring problem, I'm sending this on-list as well. Anyone who has trouble sending mail to Verizon should check their own *incoming* mail logs for connections coming from systems in 206.46.0.0/16 (GTEN-206-46), most likely 206.46.252.0/24, whose names look something like: 206.46.252.147 sv114pub.verizon.net 206.46.252.148 sv124pub.verizon.net 206.46.252.149 sv134pub.verizon.net If you're refusing those connections or blocking mail RCPT TO attempts from them, then Verizon will probably refuse your outbound SMTP traffic to them. This may not be the problem you're facing; or it may not be the only problem you're facing. But it's easy enough to check and rule out if that's the case. ---Rsk p.s. *Why* is this happening? Because Verizon has deployed a very ill-considered "anti-spam" technique ("callbacks" AKA "sender address verification") that serves three primary functions: first, it forcibly shifts the costs of Verizon's spam control onto third parties; second, it provides a spam support service; and third, it provides a free, anonymizing, scalable DDoS service.