运维分享｜安全运维之iptables防火墙（1）

[root@nto2 ~]# iptables -V
iptables v1.4.21

[root@nto2 ~]# 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=<command>  try to insert modules using this command
  --set-counters PKTS BYTES set the counter during insert/append
[!] --version   -V  print package version.