Open source firewalls

[Vinay Venkataraghavan <raghavanvinay@yahoo.com>]

Hello,

I have implemented an bare bones Intrusion detection
system that currently detects scans like open, bouce,
half open etc and a host of other tcp scans.

I would like to develop this into a full blown IDS
which is capable of detecting buffer overflow attacks,
sql injection etc. 

I know how to implement buffer overflow attacks. But
how would an intrusion detection system detect a
buffer overflow attack. My question is at the layer
that the intrusion detection system operates, how will
it know that a particular string for exmaple is liable
to overflow a vulnerable buffer. 

Are there other open source firewall implementations
other than snort?

I would apprecitate it if you could let me know.
Thanks,
Vinay



		
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