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From: "Eric Crist" <ecrist@secure-computing.net>
To: "'Mike Bruce'" <mgb@orion.org.uk>, <questions@freebsd.org>
Date: Sun, 8 Aug 2004 00:17:28 -0500
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Subject: RE: Hacker Scans - Advice requested
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> -----Original Message-----
> From: owner-freebsd-questions@freebsd.org
> [mailto:owner-freebsd-questions@freebsd.org] On Behalf Of Mike Bruce
> Sent: Sunday, August 08, 2004 12:16 AM
> To: questions@freebsd.org
> Subject: Hacker Scans - Advice requested
>
>
> Please can you help me?
>
> I am getting increasingly plagued by this message in my
> security log on my V4 installations of FreeBSD
>
> 06:48:53 mail sshd[18617]: Failed password for illegal user
> admin from 210.3.4.71 port 39741 ssh2 Aug  7
>
> Is there any way that this can be prevented without impairing
> the services provided by the operating system.
>
> Many thanks
>
> Mike Bruce

Very simple solution: create a rule to allow only traffic from known
subnets.  This will completely deny requests from IP addresses you're
not sure of.

HTH

Eric F Crist