break-in attempts on my server

Bill Horne bill at horne.net
Mon Nov 21 06:49:25 EST 2005


Kent Borg wrote:

>On Sun, Nov 20, 2005 at 06:54:44PM -0500, David Kramer wrote:
>  
>
>>That's a lot more iptables-fu than I have right now, and I
>>absolutely refuse to install iptables rules I don't understand just
>>because "I found them on the internets".
>>    
>>
>
>Dang.  I keep trying to get someone to install/figure our those
>iptables rules before I do, and no one I know will bite.
>
>  
>
>>I will attempt to understand them, though.  Thanks.
>>    
>>
>
>Let us know if you do.
>
>-kb
>
Here's my policy:

iptables -A INPUT -s 172.19.213.0/24 -p tcp --dport 22 -j ACCEPT

The input default is DENY: this rule allows only traffic from my 
internal network.

N.B.:

1. It's easy to write the rule to cover a range of IP's - and you'll be 
amazed at how
    few ranges you'll need to cover your likely access points and/or 
your friends,
    even if they use dialup.

2. As others have said, it's better to use key-based authentication than 
to use
    passwords. You KNOW they can't guess your key.

3. I prefer to block all RIPE and APNIC IP addresses; it simplifies the 
process
    a lot and I don't expect to log in from those regions anytime soon.

BIll

-- 
E. William Horne
William Warren Consulting
Computer and Network Installation & Service
http://www.billhorne.com/
Voice:	781 784-7287
Fax:	781 784-0951





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