NTP users are strongly urged to take immediate action to ensure that their NTP daemon is not susceptible to use in a reflected denial-of-service (DRDoS) attack. Please see the NTP Security Notice for vulnerability and mitigation details, and the Network Time Foundation Blog for more information. (January 2014)

Getting ntpd its Configuration

Related Items: Bug #923

Current Practice

Traditionally, ntpd gets its configuration information from /etc/ntp.conf.

Using the -C flag to specify additional configuration files

If the simulator is no longer using the -C flag then we could use -C filename to mean "process filename as an additional configuration file".

The following URL extension could also be used in this case.

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Rather than adding a -C to process an additional config file, why not simply allow -c to be specified multiple times?

BrianUtterback - 23 Oct 2007

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I'm concerned that changing the behavior of multiple -c instances would be a break with backward compatibility.

-- HarlanStenn - 23 Oct 2007

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Extending -c to allow a URL specification

The -c flag to ntpd can be used to specify the filename of an ntp.conf file.

If we allowed a URL as an argument we could support additional methods of getting this information to ntpd.

Including a local file

Syntax: ntpd -c file:///etc/ntp.conf

This is equivalent to ntpd -c /etc/ntp.conf.

Retrieving a file via HTTP

Syntax: ntpd -c http://server/ntp.conf

If the web server on server processed this URL, it could take the 'client' information from the HTTP request and customize a response.

Retrieving NTP configuration information via DHCP

Syntax: ntpd -c dhcpinfo://server

Communicate with a DHCP server to get any NTP configuration information it might have.

Related Topics: http://www.ietf.org/internet-drafts/draft-gayraud-dhcpv6-ntp-opt-00.txt

Using -e to act like a single line of a config file

I suggest adding a (possibly multiply given) -e flag that would have as its argument a string that would be processed as a single line config file.

BrianUtterback - 23 Oct 2007

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I like this and am OK with multiple -e instances.

-- HarlanStenn - 23 Oct 2007

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