Better solution for DOS attacks?

I am facing spammers everyday

[AjiNIMC]

"People will surely through stones on a fruitful tree". This phrase is the only optimistic sentence for the day when the spammers are using dialup connections (random IPs) to connect to our server. The are making 1000s of connections to jam the server promoting a DOS.

For today we banned IPs at IPtable level (thanks it is stopped now but they will surely find another network tmrw).

How do sysadmins tackle it pro actively?

Thanks,
Aji

[Matt Probert]

I know how you feel. As a site which boldy reported controversial news, we suffered a lot of DoS attacks from incensed idiots (I notice none of them came back and apologised). All we could do was monitor site access, and use IPchains (IPtables) to block offending IP addresses, much as you are doing.

Matt

[edited by: jdMorgan at 2:49 pm (utc) on June 19, 2007]
[edit reason] No politics, please. [/edit]

[AjiNIMC]

Thanks Matt,

How about limiting the connections per IP? Will this be of some help? Any disadvantages (Does google establishes more than 100 connections)?

Aji