In computing, inter-server is a technical term used in network protocol design to refer to the extension of the client-server model by having parts of a protocol which are only exchanged between the servers. In some fields server-to-server (S2S) is used as an alternative, and the term inter-domain can in some cases be used interchangeably.

Protocols that have inter-server functions as well as the regular client-server protocols include: DNS, which uses an inter-server protocol for zone transfers; the Dynamic Host Configuration Protocol (DHCP); FXP, allowing file transfer directly between FTP servers; the Inter-Asterisk eXchange (IAX); InterMUD; the IRC, an Internet chat system with an inter-server protocol allowing clients to be distributed across many servers; the Network News Transfer Protocol (NNTP); the Protocol for SYnchronous Conferencing (PSYC); SIP, a signaling protocol commonly used for Voice over IP; SILC, a secure Internet conferencing protocol and the Extensible Messaging and Presence Protocol (XMPP).

A subset of these protocols employs multicast strategies to efficiently deliver information to multiple servers in the network at once.

See also

• Overlay network

de:Server-zu-Server