Forum Moderators: bakedjake
I would like to get a mail server but would like to anonymize the IP of the mails sent out. Is this possible without using a proxy?
What do you mean by "get" a mail server? I'm going to assume that you mean setup and install a mail server on a box that you own, so you (and others) can email through it, without having the client (sender's) IP show up in the headers.
I'm also going under the assumption that it's a SERIOUS thing for people to use (ie: journalists in various countries without freedom of expression/press rights wanting to email out news, or whatever)
It is possible, for sure. Depends on how you want to go about it.
There are various email server implementations available for *NIX that you can use that will wipe the IP headers from the emails the server sends out. I haven't tried to use them in ages. The most popular are "Cypherpunk" and "Mixmaster" remailers (or used to be)... That would allow people to setup outlook express or whatnot to send email through your server.
The easiest way, though, is to either :
a) build your own PHP mailer script so that people visit a web page, type in an email, and it gets fired off without adding the originating host IP fields.
b) use something like squirrelmail, and hack it so that it doesn't add the headers. Pre-built, has full functionality, and is probably simple enough to do.
I should add, though, that if you're intending to use this as a "Truly Secure Mail Relaying System"(tm), then you're going to have to do a lot more work then that.
To truly provide for the anonimity of your users, you'll have to ensure that:
a) Logging doesn't occur *ANYWHERE* on the system. That include Apache, sendmail, PHP errors, mail pickup, syslog, etc etc etc. Basically point each and every log to /dev/null.
b) Provide an SSL interface. to your users.
d) Tell your users to PGP/GPG EVERYTHING, if they want privacy as well as anonimity.
e) Tell the users to wipe their caches (using PGP's disk wipe, or similar) regularly.
f) Ensure that your ISP is trustworthy and won't log incoming connections (hard for them to do, considering the PATRIOT act)
g) *YOU* need to re-mail your users' emails through a remailer network (look at [andrebacard.com...] for a FAQ on what I mean), otherwise there is really only a single hop between the receiver (or interceptor) of the emails and your users. That hop being you, and if you're asked nicely enough (hot irons, and various other bad things), you'll tell whoever you're trying to protect your users from, everything you know and "give up the goods", as it were.
h) IF you get caught, or something "bad" happens, you have to have a "dead man switch", where if a file or (whatever) doesn't exist, the system is wiped out. Look at various disk encryption methods that require a passphrase (GBDE for FreeBSD is beautifully designed for this kind of scenario GBDE Disk Encryption [freebsd.org] also look at the manpage for it, and the reasoning behind some of the implementations of keys, etc: GBDE Usage/Explanations [freebsd.org]
This way, combined with the other failsafes you've added into the system (no logs, etc), your users won't be able to use the system anymore, and no condemning data/email/info will pass from them through you.
If you're talking about anonimizing the IP address of the server, then use the Mixmaster/Cypherpunk remailers. Delivery isn't guaranteed, and email can take several days to get to its destination (this is done on purpose to give other servers down the line time to wipe their logs). Also, high volume (spam) traffic is normally dumped.
HTH!
-MM
