hostteil

Hostteil is a German term used in information technology and networking to denote the portion of an address that identifies the specific device on a network. In IPv4 and IPv6 contexts, the hostteil is the part of the address that remains after excluding the network or prefix portion. Its size and boundaries are determined by the subnet mask (or prefix length), which defines how many bits allocate the network portion versus the host portion within the address.

In practical terms, a hostteil identifies an individual host within a given network. For example, in a IPv4 address with a 24-bit network prefix such as 192.168.1.0/24, the networkteil is 192.168.1.0 and the hostteil comprises the final octet, allowing host addresses from 1 to 254 (with 0 as the network address and 255 as the broadcast address). The concept is central to subnetting, routing, and address allocation, where the separation into networkteil and hostteil supports scalable address management and traffic direction.

The term is most commonly encountered in German-language IT literature and teaching materials. In English-language documentation, the same idea is typically described as the host portion of an IP address or as the host identifier, with similar distinctions made for the network portion or prefix.

In the context of domain names and URLs, the word host is used differently; the host portion refers to the hostname in the URL (for example, the server name in http://server.example.com), which is a separate concept from the hostteil of an IP address. See also IP addressing, subnetting, and DNS.