1
vote
2answers
35 views

blocking udp attack ip with iptables

I was trying to block an ip of ( network stresser tool - a ddos websites selling ddos bots by seconds online ) the first one i was trying to block with iptables : iptables -A INPUT -d 173.193.26.73 ...
2
votes
1answer
181 views

SynFlood attack, spoofed IPs, syncookies mitigation

Due to a recent increase in SynFlood attacks on my company's systems i've been testing by Syn flooding the hosts myself to see how easy they are to disrupt, and the answer is 'quite easy'. By using a ...
2
votes
2answers
78 views

Will MX records with a longer TTL help mitigate effects of DoS attack?

We have our email hosted at Google Apps, and have our DNS servers for the domain setup at Namecheap. About a month ago our website went down (not a big deal, since it's most just a contact info ...
4
votes
1answer
185 views

Windows server 2008, a very small DDoS is able to kill my server

So I have this i7 3.2Ghz 6-core dedicated server running Windows Server 2008, with a 1Gbps internet speed. Everything runs fine and nice, and the machine is strong enough to handle even up to 700 ...
0
votes
2answers
228 views

netfilter ip_conntrack and (d)DoS

Does using netfilter.ip_conntrack in the kernel in anyway help mitigate (d)DoS attacks or does it make it worse? I know it adds the ability to track connections and such but just curious if it helps ...
0
votes
1answer
850 views

Best Practice for captcha based protection against D.O.S to Nginx Proxy

The idea is explained here In simple words, Nginx Proxy plays the role of load balance and transmits the HTTP/HTTPS requests to servers. If the number of request times within a certain period from ...
0
votes
2answers
432 views

Prevent scanning of the Apache's /default directory

I have two directories, under /var/www/vhosts: mydomain/ and default/. Files in default directory can be accessed using IP address of our server. I have checked Apache log and somebody is ...
1
vote
1answer
405 views

Logging UDP flood DDOS attacks? [closed]

How do I log UDP flood DDOS attacks? Right now I am thinking about detecting if the server is receiving more than X megabytes per second for Y seconds, and then doing trafshow > logs.txt as root ...
1
vote
5answers
2k views

SMTP DOS attacks with malformed email addresses

We have the following setup: Redhat kernel 2.4.16 Sendmail 8.11.6 This is a very old, ~7 years, cobalt RaQ server and is not easily upgradeable. Currently, we are being hit by multiple IP addresses ...