Let me just chime in for a sec. Even better than twidling with
hosts.[allow|deny] is a set of good block-by-default ip filtering chains.
I can't offer any actual advice on configuring ip<whater it is in linux
now> since I only expose OpenBSD to the wide internet. That's got a
totally awesome package 'ipf' (which may be supplanted with OpenIPF
shortly). In general though, it is better policy to prevent the traffic
from ever reaching tcpd.

Josh

___SIG___

On Tue, 5 Jun 2001, Brian wrote:

> On Tue, 5 Jun 2001, Dave Sherohman wrote:
>
> >
> > Nah.  They're talking to portmap, not telnetd.  Those requests are asking
> > about available RPC services, most likely in hopes of finding a vulnerable
> > NIS or NFS installation.
>
> Ok, I've heard of exploits on RPC, now I'm curious.  What's using RPC?  Is
> it just NIS and NFS?  I've heard of tons of RPC ports strewn about that
> can be exploited, it's the only remaining port that I'm worried about on
> my system.
>
> back to the original question on security, port scans are part of
> life.  Kiddies all over the internet like to run their port scanners
> because they're HACKERS and they're unstoppable!  just like in the
> movie!  *rolls eyes*  Just make sure you aren't running anything
> unnecessary, like xfs, nis, nfs, etc.  Out of curiosity, are you on a
> cable modem?  I've noticed that when I was on DSL no one even looked at my
> box but on cable in the last week I've collected large amounts of IP
> addresses probing away at my firewall.  They've mainly been targeting FTP,
> which is odd, since I hadn't had ftpd up and running at that point.  Real
> bright ones, they are! :-)
>
> tcp wrappers do a pretty good job, an ALL:ALL in hosts.deny lets me sleep
> at night anyway.  I also have a policy of denying ICMP requests on my
> outside interface just to thwart the really stupid kiddies.  Between these
> two I feel relatively secure.  Then just check your startup script to make
> sure you aren't running anything you don't need to be.
>
> -Brian
>
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