And what about denying UDP?

[Manel Marin <uni00771@pc-internet.com>]

Hi all,

Well I have clear now some things to do in my filtering packets firewall
(I have a bash script called "firewall" using ipfwadm)

- Deny SYN packets from outside (this avoid ANY connection to me from outside)
- Deny TCP inputs from outside to 1-1023 (services) and 6000-6009 (X server)

- Do some tests with ICMP to see what can be denyied without performance loss

And what about UDP?
? Just to deny inputs to 1-1023 and 6000-6009?
? Can any attack come in by UDP ports?

I have seen UDP is only used to return DNS info from port 53 (using www, ftp,
smail, and fetchmail)
? Can I deny any other UDP packet?


Again what do you thing?

Best regards,
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Manel Marin   e-mail: uni00771@pc-internet.com
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