how to detect an ip spoofing ? , is there a way to do this and know someone is pretending beeing someone else ?
thnx

I wish you luck in finding the solution dude though don't expect the bosses to understand that much. Oh by the way I am sorry I am a newbie so I can't be of much help.
Ta

Well you really can't do a whole lot about it if the attacker is outside your network and using IPs outside your network. The good news is that it's somewhat difficult to have a TCP connection spoof IPs, since you need to know both sides of it.

What you can do is setup your firewall rules so you never allow one of your networks on the wrong side of your firewall. Your external interface should block incoming packets "from" your internal network, and vis versa. It's also a good idea to block all the RFC1918 networks on your Internet interface, as well as the bogon networks.

HI

I am struggling to prevent the bogus list ..I am getting teh bogus mail in /var/spool/mail list.. I don'nt know how to prevent the bogus list?

Kindly help me to prevent ..

How to prevent the bogon network in the iptables ?

How to prevent Dos attack?

I am waiting for ur reply. Thank u very much.

Regards
Basbosco

There is a built-in spoofing filter in /proc/sys/net/ipv4/conf/all/rp_filter.

This is designed to drop packets from spoofed addresses automatically.
In /etc/sysctl.conf add net.ipv4.conf.default.rp_filter = 1 to have it start at boot..
and echo 1 > /proc/sys/net/ipv4/conf/all/rp_filter to make itactive immediately..

As far as the bogus emails are concerned, what exactly are you receiving?

DOS prevention can be handled with an iptables rule, eg
iptables -t nat -I PREROUTING -i ethx -m ! limit --limit 10/sec --limit-burst 10 -j DROP
This drops any new packets of any kind if more than 10 per second come in.
10 is a low number, so do iptables-save -c to see how many packets have been dropped by the rule and make the 10 a bit bigger for normal usage..
Be aware though, that flooding your internet connection cannot be prevented at your end, you need help from the ISP..
But your pc won't curl up and die from the traffic...