protected by spf

protected by SPF i’ve set up the dns entries for making the domains under my immediate control protected by spf.

this means that for mail transfer agents that pay attention to spf data, they will know that the mail is bogus if it claims to come from one of my domains but is not actually sent from my machine. (or any machine, for some of the domains that never send mail.)

the server has been checking spf info for a while, and it blocks a dozen or so messages a day. that’s a really tiny percentage of the 150,000 incoming messages per day, but it does show that the system works when people publish the data.

i guess the next thing to do will be to get entries set up for other domains not under my direct control, but under my influence.

there’s all sorts of interesting data i’m logging on both my own mail server and some day i should really write some tools to help analyze it. part of the problem is that there’s just too much stuff making it through the front-line filters. the smtp server still accepts about 25,000 messages a day, and even my own mail server accepts about 500 a day.

i’m still seeing about 20 spam messages get through a day. about two-thirds of that comes via work addresses (like the webmaster address), another one-sixth to my address here, and the rest via various other addresses. (that doesn’t include worms or worm-related bounces.) i could eliminate some of that by refusing mails sent via my address that is spam-tagged but still forwarded.

i’m still holding the line on doing any actual delivery-time filtering. once mail is accepted by my mail server, it goes into a regular mailbox, not something that fills up with piles of crap that i only check every three months. so when you send a mail and i don’t reply, it probably means i’m ignoring you. (don’t be offended, i do that to everyone.)

(disclaimer: spf is not the ultimate solution to kill all spam. but it would serve to eliminate some classes of spam, and helps out on the “joe job” front.)

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