Stopping Hacker Attacks

I have a linux box which is locked away and only used by me. But apparently someone is using its IP address and trying to hack into other networks (sometimes using Telnet). How can I avoid this from happening? I am using a DSL modem to access the Internet and I do not have a firewall.
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The Linux kernel has firewalling built into it.  If you are using the 2.2 kernel, the utility for setting up firewall rules is called ipchains.  A utility called ipfwadm was used with the 2.0 kernel.  If you are going to be connected to the Internet full time, as with DSL, you really must start firewalling - and since it's built into the kernel, there's no reason not to.

There is an ipchains HOWTO at the LDP (which, if you are running Red Hat and installed the "howto" RPM, is located on your system under /usr/doc/ipchains-???) which will tell you what you need to know.

Also, you should use tcp_wrappers access control facility by Wietse Venema, which comes with many Linux distributions (install the tcp_wrappers RPM if you are using Red Hat).  If it's installed, do a 'man tcpd' as a starting place.

A member of the DC LUG, Peter W, has put together a pretty
nifty script which you can edit and use to set up your own firewalling with ipchains:

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u want to hack the first u log on anonymous user..
2nd you will go /etc directory and get passwd file
some decrypting algorthims are there some sites... the gz file and comile and run it..
(note this point shadow passwd not accessiable)
you will give for shadow password ..and stop .cut ftpaccess or anonymous .
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Linux Networking

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