What is the IP protocol number for TCP?

The IP protocol number for TCP (Transmission Control Protocol) is 6. This number is part of the Internet Protocol Suite and is used to identify TCP in the header of IP packets. Each protocol in the IP suite is assigned a specific number to differentiate it from other protocols, such as UDP and ICMP. In this case, TCP's designation as protocol number 6 is essential for routers and devices on a network to recognize and appropriately handle TCP traffic, ensuring that data is transmitted reliably and in order.

Understanding this numbering is crucial for network professionals, as it helps in troubleshooting network issues related to protocol handling and configuring firewalls to allow or block specific types of traffic based on their protocol number.