USE PF to Prevent SMTP Brute Force Attacks - Resolved !!!

[Matthew Seaman]

On 16/06/2012 21:03, Shiv. Nath wrote:
> Dear Metthew,

Matthew, one a, one e.

> first thanks for assisting to secure 22/25 ports from brute force attack.
> i wish to consult if the following white list looks fine to exclude
> trusted networks (own network)
> 
> 
> 
> int0="em0"
> secured_attack_ports="{21,22,25}"
> 
> table <bruteforce> persist
> block in log quick from <bruteforce>
> pass in on $int0 proto tcp \
> from any to $int0 port $secured_attack_ports  \
> flags S/SA keep state \
> (max-src-conn-rate 5/300, overload <bruteforce> flush global)
> 
> 
> ## Exclude Own Netowrk From Brute-Force Rule ##
> 
> table <own_network> persist {71.221.25.0/24, 71.139.22.0/24}
> pass in on $int0 proto tcp from <own_network> to any
> 
> OR
> 
> pass in on $int0 proto tcp from <own_network> to secured_attack_ports
                                                   ^^^^^^^^^^^^^^^^^^^^^
                                                   $secured_attack_ports
You seem to have missed out a $ sign there.

But, yes, other than that it looks good looks good.  You want to move
the table definitions up to the top of the file and as you've shown, you
want your network specific rule after the more generic rate-limited
accept rule: remember that (except for quick rules) it's the last
matching rule in the ruleset that applies.

	Cheers,

	Matthew

-- 
Dr Matthew J Seaman MA, D.Phil.                   7 Priory Courtyard
                                                  Flat 3
PGP: http://www.infracaninophile.co.uk/pgpkey     Ramsgate
JID: matthew at infracaninophile.co.uk               Kent, CT11 9PW



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