Finally our main email server seems to be able to contact relay.verizon.net - so only a month of email gone. No idea if this is Verizon smelling coffee, or just them whitelisting us. Similarly it seems this weekend Hotmail are also happy to get email from us again. Seems hotmail.com problem was probably because one of the domains, that we forward email onto a hotmail account for, got joe jobbed. Resulting in a LOT of spam bounces being forwarded to one hotmail account over a weekend. Ironically our email server coped fine with the backscatter from the Joe Jobbing, but when hotmail servers all refused email (by failing to allow us to complete the TCP connection), the resulting increase in email processes increased the queue length to the point the email program refused incoming connections. Sometimes a polite "no thanks" is the best approach :(