[BrianFaria]

Well, it turns out that buying a linux vps 12gb of ram for hostear multiple servers, the problem that I put
"Iptables -A INPUT -p udp! --dport 7777 -j DROP" and all servers were turned off, how to fix it? How protego the vps DDoS attacks? I'm new to this, thanks!

[MCZOFT]

your missing something up here ..

PHP код:


        Syntax to block an IP address under Linux . however , you'll feel that the server went DOWN . but he's just blocked .
iptables -A INPUT -s xxx.xxx.xxx.xxx -j DROP 


as default in LINUX you need to limit using IPTABLES (linux firewall). the ammount of connections from the same IP in a short time but this will prevent the simpler DDOS attacks.
in your line , the interface name is missing . in order to adjust it and getting it ready to filter the traffic coming in . so to do so . look at the example

PHP код:

iptables -I INPUT -p udp --dport 7777 -i eth0  -m state --state NEW -m recent --set
iptables -I INPUT -p udp --dport 7777 -i eth0  -m state --state NEW -m recent --update --seconds 60 --hitcount 10 -j DROP 


Good luck

[MCZOFT]

One more thing /


If you just want to block access to one port from an ip xxx.xxx.xxx.xxx to port xxxx then type command:

PHP код:

iptables -A INPUT -s xxx.xxx.xxx.xxx -p udp --destination-port xxxx-j DROP 


The above rule will drop all packets coming from IP xxx.xxx.xxx.xxx to port mail server port xxxx.

But the DROP will not be inmediate and may need a server restart if there are already connections from the offending IP.

This scenario is common with script kiddies trying to DDOS your server.