It's the ability to have some host handle all mail for your domain when you're off line. I don't know of any free ones that do it, but on the same idea, I've got another question of whether it's easy or not. I'm wondering if there is a free service that will give me a subdomain like myhost.something.com and if people request port 80, 25, etc, to forward it to an alternate port on my machine. I mean, for example, mymachine.somehost.com port 80 forward automatically to mymachine.somehost.com port 8000, so when port 80 or whatever port is needed is requested, the client is automatically forwarded to the right port. I don't have the money for corporate access accounts with cable or dsl, and many block ports, but I'd like to be able to run my services off of the connection easily so that the in bound port is on a nonblocked port so things are as standard as possible, I was thinking of using the convention of adding two zeros to the end of all port numbers to take everything out of blocked range, easy for me to remember, but not easy to get mail through or visit websites easily on nonstandard ports, thus the need of forwarding, I may want to run cgis, so I probably will need control of the system, especially admin scripts that I may use when I'm not at the linux box so I can disable or restrict telnet to certain ips, which is hard to do on a dynamic ip, maybe webmin or something to bring up the telnet interface when I'm ready to use it, and shut it down when I'm through with it, or various other interesting things, hosting them on someone else's server would be difficult as they've got to be setuid, over the internet to control my machine instead of their's, not only that I hate the ads and proprietary clients many free providers use to upload, as the ftp servers are often down, busy, or slow.
