🚀 go-pugleaf

Paul Richards <pauldoo@dunvegan1.demon.co.uk> doodled in uk.comp.os.linux:

> I've recently got my Linux (Debian) box set up back to how it was before
> I broke it.  (Well M$ FDISK decided to make a FAT32 partition overlap my
> EXT2 which was nice when I tried to format the FAT32..)  What should I
> do to make the system more secure?  I no longer have dual boot, only
> Linux because I was pissed off with what M$ FDISK done.

Too right! Nuke that evil m$loth scum :)

> I'm only on a dialup box and I have no local network.  Any tips/ideas?
> 
> I need to have http and anonymous ftp connections allowed and I also
> need to be able to telnet in.

Okiedokies... as someone's already said, don't run any services you don't
really need - start by disabling things in /etc/inetd.conf, and check with
netstat -ant | grep LISTEN to see what other standalone daemons you've got
running. (You can use  fuser -n tcp port#   to see what process is using a
particular port if it's not running out of inetd.)

What I'd also recommend is getting a firewall that blocks all new incoming tcp
connections between 1-1024, apart from 22 and 80. (I find ftp expendable,
especially if you've got a way of accessing ~ftp over http or ssh, but YMMV as
always.)

Play with ipchains a bit - in particular you want -y to stop all new incoming
tcp connections whilst permitting packets to come back to a low source port,
and -l to log failures.
(When designing a firewall for dialup purposes, don't use specific IP#s
especially if you have dynamic IP, but deal in terms of -i ppp0, of course.
You might want to use ipchains-save and ipchains-restore to preserve the
firewall and restore it on dialup automatically.)

What you might also like to consider is running fakebo - this is a standalone
daemon that listens for incoming Back Orifice scans and optionally sends crap
back - in the space of two weekends I caught as many scans over even a dynamic
dialup IP range...

~Tim
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