Installing A Secure FreeBSD Box

ltwally writes "The guys over at LittleWhiteDog have a how-to on securing FreeBSD. Topics range from the basics to custom kernels, blowfish encryption, smtp, and custom firewall scripts. Definitely worth a look if you're running a FreeBSD box, or are interested in *nix security in general."

Comments

Re:Sendmail

[scrytch]

587 is the "mail submission port", and is designed to be the port on which mail is originated, leaving port 25 for transferring mail between MTA's. This has various properties in that they can treat authentication differently (SMTP auth is required on port 587), and therefore has a number of anti-spam properties as well as some other benefits. Obviously port 25 is not going away for MSA's anytime soon, but it's a step. One big adopter of this is AOL: AOL users using AOL network services (e.g. corporate accounts) already are required to use port 587 when not using an AOL dialup, as AOL already rejects direct-to-MX on port 25 for most dynamic IP's.

It's all spelled out in RFC2476