iptables

http://linux.vbird.org/linux_server/0250simple_firewall.php#netfilter

iptables 是利用封包过滤机制, 分析封包的表头资料,根据表头资料定义的规则来决定是否可以进入主机或者被丢弃.

刚才在服务器上练习的时候把自己给屏蔽了,提醒大家拿其他同学的ip做练习,哈哈.

$iptables [-t tables] [-L] [-nv]

-t: 后面接table,  例如nat 或者filter,如果省略此项目,则使用预设的filter

-L:列出目前的table的规则

-n: 不进行IP与HOSTNAME的反查

-v: 列出更多的信息,包括通过该规则的封包总位元数等

tty:[0] jobs:[0] cwd:[/opt/app]14:50 [root@a]$ iptables -L -nChain INPUT (policy ACCEPT)target     prot opt source               destination         DROP       all  --  10.103.55.165        0.0.0.0/0           Chain FORWARD (policy ACCEPT)target     prot opt source               destination         Chain OUTPUT (policy ACCEPT)target     prot opt source               destination  

15:08 [root@a]$ iptables -hiptables v1.3.5Usage: iptables -[AD] chain rule-specification [options]       iptables -[RI] chain rulenum rule-specification [options]       iptables -D chain rulenum [options]       iptables -[LFZ] [chain] [options]       iptables -[NX] chain       iptables -E old-chain-name new-chain-name       iptables -P chain target [options]       iptables -h (print this help information)Commands:Either long or short options are allowed.  --append  -A chainAppend to chain  --delete  -D chainDelete matching rule from chain  --delete  -D chain rulenumDelete rule rulenum (1 = first) from chain  --insert  -I chain [rulenum]Insert in chain as rulenum (default 1=first)  --replace -R chain rulenumReplace rule rulenum (1 = first) in chain  --list    -L [chain]List the rules in a chain or all chains  --flush   -F [chain]Delete all rules in  chain or all chains  --zero    -Z [chain]Zero counters in chain or all chains  --new     -N chainCreate a new user-defined chain  --delete-chain            -X [chain]Delete a user-defined chain  --policy  -P chain targetChange policy on chain to target  --rename-chain            -E old-chain new-chainChange chain name, (moving any references)Options:  --proto-p [!] protoprotocol: by number or name, eg. `tcp'  --source-s [!] address[/mask]source specification  --destination -d [!] address[/mask]destination specification  --in-interface -i [!] input name[+]network interface name ([+] for wildcard)  --jump-j targettarget for rule (may load target extension)  --goto      -g chain                              jump to chain with no return  --match-m matchextended match (may load extension)  --numeric-nnumeric output of addresses and ports  --out-interface -o [!] output name[+]network interface name ([+] for wildcard)  --table-t tabletable to manipulate (default: `filter')  --verbose-vverbose mode  --line-numbersprint line numbers when listing  --exact-xexpand numbers (display exact values)[!] --fragment-fmatch second or further fragments only  --modprobe=<command>try to insert modules using this command  --set-counters PKTS BYTESset the counter during insert/append[!] --version-Vprint package version.

接下来新建一条

15:10 [root@a]$ iptables -A INPUT -s 16.16.136.66 -j DROP

由于写的是自己的ip地址,回车后已不能继续在服务器上继续操作...只能找同学帮忙删了服务器上的配置

查看一下

15:12 [root@a]$ iptables -L -nChain INPUT (policy ACCEPT)target     prot opt source               destination         DROP       all  --  10.166.16.66        0.0.0.0/0           DROP       all  --  16.16.136.66         0.0.0.0/0           Chain FORWARD (policy ACCEPT)target     prot opt source               destination         Chain OUTPUT (policy ACCEPT)target     prot opt source               destination  

删除刚才新建的那条

15:12 [root@a]$ iptables -D INPUT 2