linux：iptables (3) 命令行操练（一）

目录

1.命令行手册查缺补漏

1.1 默认全局参数

 1.2 关于icmp的参数指令

1.3 关于tcp的参数指令

2.开始练习,从最陌生的参数练习开启

2.1 --list-rules  -S ：打印链或所有链中的规则

2.2 --zero -Z 链或所有链中的零计数器

 2.3 --policy  -P 修改默认链的默认规则

2.4 --new -N 接下来练习添加和删除自定义链

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1.命令行手册查缺补漏

1.1 默认全局参数

[root@ovn-center ~]# iptables --help
iptables v1.4.21

Usage: iptables -[ACD] chain rule-specification [options]
       iptables -I chain [rulenum] rule-specification [options]
       iptables -R chain rulenum rule-specification [options]
       iptables -D chain rulenum [options]
       iptables -[LS] [chain [rulenum]] [options]
       iptables -[FZ] [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 chain            Append to chain
  --check   -C chain            Check for the existence of a rule
  --delete  -D chain            Delete matching rule from chain
  --delete  -D chain rulenum
                                Delete rule rulenum (1 = first) from chain
  --insert  -I chain [rulenum]
                                Insert in chain as rulenum (default 1=first)
  --replace -R chain rulenum
                                Replace rule rulenum (1 = first) in chain
  --list    -L [chain [rulenum]]
                                List the rules in a chain or all chains
  --list-rules -S [chain [rulenum]]
                                Print the rules in a chain or all chains
  --flush   -F [chain]          Delete all rules in  chain or all chains
  --zero    -Z [chain [rulenum]]
                                Zero counters in chain or all chains
  --new     -N chain            Create a new user-defined chain
  --delete-chain
            -X [chain]          Delete a user-defined chain
  --policy  -P chain target
                                Change policy on chain to target
  --rename-chain
            -E old-chain new-chain
                                Change chain name, (moving any references)
Options:
    --ipv4      -4              Nothing (line is ignored by ip6tables-restore)
    --ipv6      -6              Error (line is ignored by iptables-restore)
[!] --protocol  -p proto        protocol: 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 target
                                target for rule (may load target extension)
  --goto      -g chain
                              jump to chain with no return
  --match       -m match
                                extended match (may load extension)
  --numeric     -n              numeric output of addresses and ports
[!] --out-interface -o output name[+]
                                network interface name ([+] for wildcard)
  --table       -t table        table to manipulate (default: `filter')
  --verbose     -v              verbose mode
  --wait        -w [seconds]    maximum wait to acquire xtables lock before give up
  --wait-interval -W [usecs]    wait time to try to acquire xtables lock
                                default is 1 second
  --line-numbers                print line numbers when listing
  --exact       -x              expand numbers (display exact values)
[!] --fragment  -f              match second or further fragments only
  --modprobe=          try to insert modules using this command
  --set-counters PKTS BYTES     set the counter during insert/append
[!] --version   -V              print package version.

 1.2 关于icmp的参数指令

icmp match options:
[!] --icmp-type typename        match icmp type
[!] --icmp-type type[/code]     (or numeric type or type/code)
Valid ICMP Types:
any
echo-reply (pong)
destination-unreachable
   network-unreachable
   host-unreachable
   protocol-unreachable
   port-unreachable
   fragmentation-needed
   source-route-failed
   network-unknown
   host-unknown
   network-prohibited
   host-prohibited
   TOS-network-unreachable
   TOS-host-unreachable
   communication-prohibited
   host-precedence-violation
   precedence-cutoff
source-quench
redirect
   network-redirect
   host-redirect
   TOS-network-redirect
   TOS-host-redirect
echo-request (ping)
router-advertisement
router-solicitation
time-exceeded (ttl-exceeded)
   ttl-zero-during-transit
   ttl-zero-during-reassembly
parameter-problem
   ip-header-bad
   required-option-missing
timestamp-request
timestamp-reply
address-mask-request
address-mask-reply

1.3 关于tcp的参数指令

tcp match options:
[!] --tcp-flags mask comp       match when TCP flags & mask == comp
                                (Flags: SYN ACK FIN RST URG PSH ALL NONE)
[!] --syn                       match when only SYN flag set
                                (equivalent to --tcp-flags SYN,RST,ACK,FIN SYN)
[!] --source-port port[:port]
 --sport ...
                                match source port(s)
[!] --destination-port port[:port]
 --dport ...
                                match destination port(s)
[!] --tcp-option number        match if TCP option set

2.开始练习,从最陌生的参数练习开启

2.1 --list-rules  -S ：打印链或所有链中的规则

[root@ovn-center ~]# iptables --list-rules
-P INPUT ACCEPT
-P FORWARD ACCEPT
-P OUTPUT ACCEPT
[root@ovn-center ~]# iptables -t nat --list-rules
-P PREROUTING ACCEPT
-P INPUT ACCEPT
-P OUTPUT ACCEPT
-P POSTROUTING ACCEPT
[root@ovn-center ~]# iptables -t filter -S
-P INPUT ACCEPT
-P FORWARD ACCEPT
-P OUTPUT ACCEPT
-A INPUT -s 10.10.10.3/32 -j DROP

2.2 --zero -Z 链或所有链中的零计数器

 2.3 --policy  -P 修改默认链的默认规则

在修改了filter表的INPUT默认规则为DROP时，直接断网 ，

也就是丢弃了所有一切进入主机的数据包

 需要给指定的链修改默认规则，而无法一次性全部修改

我们恢复规则继续测试

2.4 --new -N 接下来练习添加和删除自定义链

在filter表上添加一个链

iptables -t filter -N WEB

接着将WEB引用到filter表INPUT链，这样凡是目标端口是80，443的流量都将经过WEB链的规则

 删除自定义链表的时候，不能有引用和规则，需要清理关系和内部的规则