How to block ports on Linux VPS.

[digimon]

can any1 help me please? cause I am providing vpn and some of my clients use it to spam emails. cause when connected to server it will look like its from the server but it is not. its from the clients PC/Laptop. Its because their ip is change using the server.

so I need someone who can help me stop them in sending emails. using their laptops/computers. by blocking ports maybe?

I am willing to pay. Upfront if trusted person.

maybe with this ssh command? iptables -A OUTPUT -p tcp --dport 25 -j DROP

 

[jayfella]

Link: http://www.cyberciti.biz/tips/linux-iptables-15-how-to-block-or-open-mail-serversmtp-protocol.html

To verify if you have done it correctly: http://kb.siteground.com/article/How_to_check_whether_SMTP_port_25_is_blocked.html

 

[digimon]

added this 2 commands..

iptables -A OUTPUT -p tcp --dport 25 -j DROP
iptables -A OUTPUT -p udp --dport 25 -j DROP


but after applying that. the speed using the VPN on the server. is getting only 1-7kb/sec.. huhu!

 

[jayfella]

That isn't what the tutorial instructs you do to. Furthermore, closing port 25 wont have absolutely any effect of the speed of the VPN whilst browsing the internet. Do as the instructions say. I cannot and will not help you if you ignore my instructions.

 

[digimon]

okay I'm going to try this..

iptables -A OUTPUT -p tcp -s server.ip.add.res --sport 25 -d 0/0 --dport 1024:65535 -m state --state ESTABLISHED -j REJECT

hope it will work.