Umm, hokay. I'll be honest and admit that this is a pant browning moment. I get the non static IPs for the router. No problem there - that I could probably manage. Probably. Question is...how does that then equate to an exchange server sending and receiving email? Sorry chaps, I know everyone is being really helpful, but you're olympians and I'm more of a family bike ride. Assuming I have No-IP set up, and NOIP knows where I am, and my internal network is using say niknet.org as my domain name, and my exchange server is sending mail for niknet.org (internally), who gets the DNS information? getting stuff out is relatively easy, as once a packet is forwarded to the "outside" then it's out, but people knowing where to get back in worries me. Does the FQDN then have to be public? Start again - if I use my public FQDN for my internal network of ten or so machines, yet put those on private addresses (192.X) will I still be able to send and receive email using SMTP, and, crucially allow other people to send me email to the public email address (which, in theory it would be as it'd be globally visible yet hidden). I do a lot of thinking aloud.Sorry. All thoughts gratefully received. Cheers, Nick