Shulou(Shulou.com)06/01 Report--

1. So that only 192.168.0.x and 192.168.0.y machines can connect to your pop3 server. But other people in the same segment can't. [answer: POP3 is the receiving server, default port is 110, SMTP is the sending server Default port 25] #! / bin/bash for i in net filter mangle do iptables-t $I-F iptables-t $I-X done ip = "192.168.0" iptables-t filter-An INPUT-p tcp-s $ip.x-- dport 110-j ACCEPT iptables-t filter-An INPUT-p tcp-s $ip.y-- dport 110-j ACCEPT iptables-t filter-An INPUT-p tcp-s $ip.0/24-- dport 110-j REJECT- -2. Set the default policy to INPUT and OUTPUT to deny all, but: allow you any access to your own ip addresses (192.168.0.11 and 127.0.0.1). #! / bin/bash for i in net filter mangle do iptables-t $I-F iptables-t $I-X done iptables-An INPUT-s 192.168.0.11-j ACCEPT iptables-An OUTPUT-d 192.168.0.11-j ACCEPT iptables-An INPUT-s 127.0.0.1-j ACCEPT iptables-An OUTPUT-d 127.0.0.1-j ACCEPT iptables-P INPUT REJECT iptables-P OUTPUT REJECT # iptables-An INPUT-j REJECT # iptables-An OUTPUT-j REJECT -3. Only two people, that is, two hosts, are allowed to telnet you. For example, one of them is 192.168.0.123 #! / bin/bash for i in net filter mangle do iptables-t $I-F iptables-t $I-X done ip = "192.168.0" iptables-An INPUT-s ip.123-- dport 23-j ACCEPT iptables-An INPUT-s ip.x-dport 23-j ACCEPT iptables-An INPUT-- dport 23-j REJECT-- -- 4. Allow two people to ping you once per second [ping type=8] #! / bin/bash iptables-F iptables-t nat-F iptables-X iptables-t nat-X iptables-An INPUT-s 192.168.1.x-p icmp--icmp-type 8-m limit-- limit 1Universe s-j ACCEPT iptables-An INPUT-s 192.168.1.y-p icmp--icmp-type 8-m limit-limit 1Bank s-j ACCEPT-- -5. Allows you to actively visit anyone #! / bin/bash iptables-F iptables-t nat-F iptables-X iptables-t nat-X iptables-An OUTPUT-p tcp--tcp-flags SYN,ACK,RST SYN-j ACCEPT iptables-An INPUT-p tcp--tcp-flags SYN,ACK RST SYN-j REJECT-6.Test01 users can use their own ip addresses for testing purposes But cannot access any other ip-7.Test02 users can access any address #! / bin/bash iptables-F iptables-t nat-F iptables-X iptables-t nat-X iptables-A INPUT-s Test02-j ACCEPT iptables-P INPUT REJECT-8. Define a custom rule to log all actions that access your port 23. #! / bin/bash iptables-F iptables-t nat-F iptables-X iptables-t nat-X iptables-An INPUT-dport 23-j LOG-log-level info-- log-prefix "iptables"

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