5
votes
4answers
1k views

How to stop a ICMP attack?

We are under a heavy icmp flood attack. Tcpdump shows the result below. Altough we have blocked ICMP with iptables tcpdump still prints icmp packets. I've also attached iptables configuration and ...
3
votes
2answers
629 views

iptables rate-limit module problem

I am using iptables' rate-limit module to prevent DoS attack (I know it cannot stop a full scale DDoS but at least it can help with smaller attacks). In my rules I have something like: ...
0
votes
2answers
208 views

iptables logs but doesn't drop packets

I am trying to create some simple iptables DOS protection rules for my web server. I was doing testing on the following rules: iptables -N LOGDROP > /dev/null 2> /dev/null iptables -F LOGDROP ...
1
vote
3answers
438 views

Fail2ban advice on banning IP's and HTTP

I've recently installed fail2ban as a way of keeping one of our web servers secure from SSH attacks and HTTP attacks. At the moment I'm getting a lot of ssh attacks but fail2ban are banning and then ...
0
votes
2answers
634 views

what should be limit to use for IPTABLE rate limiting for a webserver

I see on my webserver some logs as follows 203.252.157.98 - :25:02 "GET //phpmyadmin/ HTTP/1.1" 404 393 "-" "Made by ZmEu @ WhiteHat Team - www.whitehat.ro" 203.252.157.98 - :25:03 "GET ...
2
votes
2answers
436 views

How do you stop PINGs from causing a DOS on a Linux server?

Have a CentOS-5.x box that appears to be going down as a result of PINGs. If the server gets PINGs it stops replying to ssh/http connections. Appears iptable is one approach, but I want to make sure ...
0
votes
4answers
684 views

Preventing Denial of Service Attacks

What's the most effecient way to prevent DoS attacks for game servers? Currently I do something like this: iptables -A INPUT -p udp --dport 27015 -m length --length 28 -j DROP Is it the best way?
1
vote
3answers
154 views

What is the best way to prevent somone abusing access to your site using scripts?

What is the best way to prevent someone abusing access to your site using scripts?