Palestra de Wietse Venema no FISL 11

Finalmente consegui tempo para postar sobre o FISL 11. Essa edição contou com a presença de Wietse Venema, que veio falar, é claro, sobre Postfix, um dos mais utilizados servidores de e-mail do mundo.




Algumas anotações que fiz durante a palestra:

- Security is hard
- Buggy programs still works
- Plan for failure (less impact in case of failure)
- Errors from others is a oppotunity to learn
- Junk mail is war. RFC is no applyed in it
- Invent sparingly
1999 - Melissa ravages the internet
/ˆSubject:.*Important Message From/ REJECT

- It is never to late to do something right (after-queue content filter support in Postfix 2.6)
- Before-queue content inspection via SMTP: Respond to popular demand (Europe), despite performance limitation
- It's not spammer's who destroy e-mail - Wietse, postfix list, 2003
- 2005: Proliferation of authentication tecnologies - SPF, SenderID, DKIM, BATV, SRS, ADSP - Solution: adopt sendmail milter protocol (have to look in the sendmail source code to do it)
- In 2006, Postfix author receives the Sendmail Inovation Award because of his work in sendmail milter (funny, no?)
- Putting more funcionality into fewer lines od code
- Postfix market share: ~ 8,6%



- "Zombies suck the life out of the mail server"
- RFC 5321 recommends 5 minutes server-side timeout. Result: all SMTP server ports are busy by zombies
- Postfix >= 2.3 logs äll server ports busy" warnings
- Work faster: spend less time (ex: 10 seconds)
- smtp_timeout, smtp_hard_error_limit, smtp -o stress=yes
- Persistent overload_before_smtpd connection filter (POSTSCREEN)
- Parallel "screening" of multiple connections
- Pregreet improved to catch zombies (zombies responds to fast)





E, como não podia faltar, uma foto junto com o Wietse: :-)