practice Archives - admins 24x7

NTP Server Setup: Time synchronization

Published on March 8, 2014

NTP Server Setup: Time synchronization Network Time Protocol (NTP) is a networking protocol for clock synchronisation between computer systems over packet-switched, variable-latency data networks. In operation since before 1985, NTP is one of the oldest Internet protocols in use. NTP was originally designed by David L. Mills of the University of Delaware, who … Continue reading NTP Server Setup: Time synchronization

Linux iptables

Published on December 11, 2013

Linux iptables First off all we should set policy for our firewall: iptables -P Example:

iptables -P INPUT ACCEPT

1	iptables -P INPUT ACCEPT

To show current status of our firewall – iptables: NOTE: this doesn’t mean rules are in /etc/iptables.rules file.

iptables --list --line-numbers -n

1	iptables --list --line-numbers -n

Same, but a little shorter:

iptables -L -n --line-numbers

1	iptables -L -n --line-numbers

keys: -n – do not resolv service names -L / –list – lists rules … Continue reading Linux iptables