From the course: CompTIA Network+ (N10-009) Cert Prep

Network time protocol (NTP)

From the course: CompTIA Network+ (N10-009) Cert Prep

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Network time protocol (NTP)

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- One of my favorite movies to watch is "Back to the Future". And one of the coolest scenes is when Doc Brown had all those clocks synchronized and they all went off at the same time. If Doc Brown could do it almost 40 years ago, we can definitely do it today. Enter NTP, Network Time Protocol and it's lightweight buddy, SNTP for Simple Network Time Protocol. They use UDP to sync up clocks and devices on a network. Computers need to be on the same time, so things like Kerberos authentication, work smoothly. Don't stress about Kerberos now. It's just an authentication method that you'll learn about later. If your device needs NTP or SNTP, you can enter the IP address for the server. Keep in mind that in big organizations, this is handled by the admin team. Just also remember that NTP and SNTP both use Port 123. Now, how does all of this actually work? NTP operates in a layered system called Clock Strata. At the top, we've got stratum zero devices and the atomic clocks or the GPS system. These keep near perfect time. Servers that connect to these are Stratum one servers syncing within a few milliseconds of Stratum zero. Then we have Stratum two clients connecting to Stratum one servers and so on down to Stratum all the way to 15. After that, devices just aren't synced anymore. In simple terms, the closer you are to the top, the more accurate your time. As you go down the levels, synchronization gets a little bit looser until Stratum 15 is done. Now, NTP is awesome because it can protect you from certain issues. Think about logging into a secure website and then stepping away for a while. It logs you out after some time for security reasons. This wouldn't work if the server was on one time zone and you were in another without NTP synchronizing everything up between the two of you. But hey, nothing's perfect. NTP has its downsides. It's not useful if you need time accuracy beyond milliseconds. Also, any network delays can mess with its accuracy, plus it can be vulnerable to attacks. To beef up security, there's the network time security protocol. NTS adds encryption to the timing system through NTS Key Exchange, otherwise known as NTS-KE. It's based on TLS with NTP extensions. Here's how NTS works. A client sends a key exchange using NTS-KE, creating secret keys and cookies for communication. The client then uses these to query the server for time with the server validating and responding with a new cookie for continued secure communication. Another cool protocol is Precision Time Protocol. You got it. PTP, which syncs clocks with microsecond accuracy, especially useful in distributed networks. PTP supports both one way and two way sync and needs specialized nicks for hardware time stamping. PTP works in two modes. One step, direct sync from master clock to device and two step intermediate transparent clocks forward sync messages. One step is better for smaller networks while two step suits larger ones. PTP shines in finance, syncing trades, telecom with voiceover IP calls, video streaming, and industrial automation coordinating control systems and robotics. So while time may seem just like an idea in the network plus world, it needs to be precise as possible.

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