GRC | Port Authority, for Internet Port 123

Port Authority Edition – Internet Vulnerability Profiling
by Steve Gibson, Gibson Research Corporation.

Goto Port 122

Probe Port 123


Enter Port: 0-65535

Goto Port 124

Port Authority Database

Port 123

Name:	ntp
Purpose:	Network Time Protocol
Description:	The network time protocol is a clean, simple, lightweight, and efficient protocol allowing clients to query servers for the current time (including the date). The only glitch is that the 64-bit NTP time value will overflow (suddenly go back to zero) in early February (the 6th or 7th, no one seems to be sure which) in the year 2036. I plan to be relaxing on a beach somewhere on that day.
Related Ports:	-

Background and Additional Information:

Extremely accurate NTP servers are scattered all across the Internet. Many ISP routers run NTP servers and freely offer up the time to any client who queries.

If you're not sure whether your ISP is offering local NTP servers, you can discover the IPs of the Internet routers near you with a simple "tracert" (Trace Route) command: Open an MS-DOS window and issue the command "tracert microsoft.com". You will receive a listing of the IP addresses of the routers closest to you and moving away in the direction of Microsoft.

Next, point your favorite NTP time-setting client program at one of the nearby IPs and see whether it can retrieve a time and date. If not, try another.

The NTP time format is a simple 64-bit number which uses the most significant 32-bits to represent the number of seconds which have elapsed since Midnight of January 1st, 1900. The least significant 32-bits represent the fraction of that second which have elapsed.

The NTP RFC

An extremely detailed and scholarly specification of the predominant Internet time protocol:

http://www.ietf.org/rfc/rfc1305.txt

http://www.faqs.org/rfcs/rfc1305.html

Trojan Sightings: Net Controller

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