UDP 123

Looking for information on Protocol UDP 123? This page will attempt to provide you with as much port information as possible on UDP Port 123.

UDP Port 123 may use a defined protocol to communicate depending on the application. A protocol is a set of formalized rules that explains how data is communicated over a network. Think of it as the language spoken between computers to help them communicate more efficiently.

Protocol HTTP for example defines the format for communication between internet browsers and web sites. Another example is the IMAP protocol that defines the communication between IMAP email servers and clients or finally, the SSL protocol which states the format to use for encrypted communications.

UDP Port 123

Here is what we know about protocol UDP Port 123. If you have information on UDP port 123 that is not reflected on this page, simply leave a comment and we’ll update our information.

PORT 123 – Information

• Port Number: 123
• TCP / UDP: UDP
• Delivery: No
• Protocol / Name: ntp
• Port Description: Network Time Protocol. Provides time synch between computers and network systems. Assists in database mgmt, auth schemes, and audit/logging accuracy. Security Concerns: It provides both info and an avenue of attack for intruders. Info gathered can include: system uptime, time since reset, time server pkt, I/O, & memory statistics, and ntp peer list. Further, if a host is susceptible to time altering via ntp, an attacker can: 1) Run replay attacks, using captured OTP and Kerberos tickets before they expire. 2) Stop security-related cron jobs from running or cause them to run at incorrect times. 3) Make system and audit logs unreliable, since time is alterable.
• Virus / Trojan: No

  Tip! Use our free Digital Footprint and Firewall Test to help verify you are not infected.

Side note: UDP port 123 uses the Datagram Protocol, a communications protocol for the Internet network layer, transport layer, and session layer. This protocol when used over PORT 123 makes possible the transmission of a datagram message from one computer to an application running in another computer. Like TCP (Transmission Control Protocol), UDP is used with IP (the Internet Protocol) but unlike TCP on Port 123, UDP Port 123 is connectionless and does not guarantee reliable communication; it’s up to the application that received the message on Port 123 to process any errors and verify correct delivery.

Because protocol UDP port 123 was flagged as a virus (colored red) does not mean that a virus is using port 123, but that a Trojan or Virus has used this port in the past to communicate.

UDP 123 – Disclaimer

We do our best to provide you with accurate information on PORT 123 and work hard to keep our database up to date. This is a free service and accuracy is not guaranteed. We do our best to correct any errors and welcome feedback!

Comments

1. Dave says:
   January 11, 2012 at 2:21 am

   no. it means that your firewall is blocking the windows time service. it means that your time wont sync with the NTP servers.

   if youre confident in the clock on your PC, theres no reason to have port 123 open. just close it.

   then if you want to stop the firewall errors, just stop the windows time service.
2. georgy paul says:
   October 29, 2010 at 7:45 pm

   my defensewall firewall tells

   Attempt to set value Desktop within the key HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders\
   Attempt to post message 412 into the window of the process D:\WINDOWS\explorer.exe.
   Attempt of connect to the UDP port 123
   Attempt to set value Common AppData within the key HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders\
   what does it mean is it hacked