rdate down?

I was unable to reproduce a network time-out when testing from three different external locations; however, there are multiple possible reasons why this could occur. This could be either a temporary issue with the specific httpupdate/time server being connected to, a firewall configuration if one is used on the local system, or it could be localized to an upstream data center or network carrier.

Via root SSH access, please let us know the output of the following command:

Code:

# ping -vc10 rdate.cpanel.net
# traceroute -v rdate.cpanel.net

For potential alternatives (via IP addresses), the following command could be used:

Code:

# dig rdate.cpanel.net +noall +answer

I recommend using NTP via a customized NTP daemon ("ntpd") configuration so that a service will stay running to regulate the accuracy of the local system time. For details, I would suggest ensuring your system has the "ntp" package installed and then refer to official manual ("man") documentation pages using the following commands:

Code:

# man ntpd
# man ntp.conf

If the software package "ntp" is installed here is an alternative to "rdate" that will work when the NTP daemon ("ntpd") is not yet enabled:

Code:

# ntpdate -v clock.isc.org

 

Do you have any firewall configurations in-place? It is possible that rdate may be unable to communicate via the required ports (e.g., destination port 37, for rdate, and destination port 123, for ntp).

On a Linux system with iptables, the following may be used to verbosely list all iptables rules:

Code:

# iptables -L -nv

If there are custom rules (more than just the stock-default entries), I would consider temporarily stopping the firewall; the procedure for this may vary depending on how the firewall rules were setup.

Warning: Caution should be exercised to avoid accidental connectivity loss when temporarily shutting down any active firewalls; if there is any uncertainty regarding the firewall configuration I recommend consulting with the hosting service provider or applicable on-site data center staff.

As an example, if iptables is used alone (without any wrapper scripts like CSF or APF) then the following should perform the step of saving any current rules, then stopping the firewall:

Code:

# /etc/init.d/iptables save
# /etc/init.d/iptables stop

If an iptables wrapper script was used to configure the firewall then a different procedure may be necessary; here is an example if using CSF as the iptables wrapper:

Code:

# /usr/sbin/csf -f

Manually running rdate or ntpdate may be performed as seen in the following examples:

For rdate, via TCP, destination port 37:

Code:

# rdate -s rdate.cpanel.net

For rdate, via UDP, destination port 37:

Code:

# rdate -s -u rdate.cpanel.net

For ntpdate, via UDP, destination port 123, with verbose output:

Code:

# ntpdate -v clock.isc.org

Installing the NTP software package "ntp" will provide both the NTP daemon "ntpd" as well as the utility "ntpdate" to manually set time when not running ntpd; the following commands may be used to accomplish the installation, varying depending on the OS:

For CentOS/RHEL (i.e., RPM-based Linux):

Code:

# /scripts/ensurerpm ntp

For FreeBSD:

Code:

# /scripts/ensurepkg ntp

 

NTPd should be very low on resource usage; I'm not aware of any significant load increase as a result of running ntpd to maintain accurate system time.

The UDP option may not work as I first believed; however, the default TCP method should work without issue, as seen below:

Code:

# rdate -s rdate.cpanel.net

To further clarify, it is the TCP method that is used by cPanel, as seen in the following example entry in rc.local:

Code:

# grep rdate /etc/rc.d/rc.local
rdate -s rdate.cpanel.net&

 

Expanding upon the last message, when I tested the specific httpupdate mirror IP address I was able to display the retrieved date and time via the rdate option "-p" for print:

Code:

# rdate -p rdate.cpanel.net
rdate: [rdate.cpanel.net]	Sat Mar 20 03:14:01 2010

# rdate -ps rdate.cpanel.net
rdate: [rdate.cpanel.net]	Sat Mar 20 03:14:02 2010

# rdate -p 208.74.121.37
rdate: [208.74.121.37]	Sat Mar 20 03:16:01 2010

# rdate -ps 208.74.121.37
rdate: [208.74.121.37]	Sat Mar 20 03:16:03 2010