You want to delete firewall rules, individually or all at once.
To delete rules en masse, also called flushing a chain, do the following:
For iptables:
# iptables -F [chain]
For ipchains:
# ipchains -F [chain]
To delete rules individually:
For iptables:
# iptables -D chain rule_number
For ipchains:
# ipchains -D chain rule_number
Rules are numbered beginning with 1. To list the rules:
# iptables -L # ipchains -L
select one to delete (say, rule 4 on the input chain), and type:
# iptables -D INPUT 4 # ipchains -D input 4
If you've previously saved your rules and want your deletions to remain in effect after the next reboot, re-save the new configuration. [Recipe 2.19]
iptables(8), ipchains(8).