Looking for information on Protocol TCP 21? This page will attempt to provide you with as much port information as possible on TCP Port 21.
TCP Port 21 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.
TCP Port 21
Here is what we know about protocol TCP Port 21. If you have information on TCP port 21 that is not reflected on this page, simply leave a comment and we’ll update our information.
PORT 21 – Information
- Port Number: 21
- TCP / UDP: TCP
- Delivery: Yes
- Protocol / Name: [Malware known as WinCrash]
- Port Description: [malware info: WinCrash]
- Virus / Trojan: Yes, Caution!
Use our free Digital Footprint and Firewall Test to help verify you are not infected.
Side note: TCP port 21 uses the Transmission Control Protocol. TCP is one of the main protocols in TCP/IP networks. Whereas the IP protocol deals only with packets, TCP enables two hosts to establish a connection and exchange streams of data. TCP guarantees delivery of data and also guarantees that packets will be delivered on port 21 in the same order in which they were sent. Guaranteed communication over port 21 is the key difference between TCP and UDP. UDP port 21 would not have guaranteed communication in the same way as TCP.
Because protocol TCP port 21 was flagged as a virus (colored red) does not mean that a virus is using port 21, but that a Trojan or Virus has used this port in the past to communicate.
TCP 21 – Disclaimer
We do our best to provide you with accurate information on PORT 21 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!