5.9. Other miscellaneous network related configuration files.

There are a number of miscellaneous files relating to network configuration under linux that you might be interested in. You may never have to modify these files, but it is worth describing them so you know what they contain and what they are for.

5.9.1. `/etc/protocols`

The /etc/protocols file is a database that maps protocol id numbers against protocol names. This is used by programmers to allow them to specify protocols by name in their programs and also by some programs such as tcpdump to allow them to display names instead of numbers in their output. The general syntax of the file is:

protocolname number aliases

The /etc/protocols file supplied with the Debian distribution is as follows:

# /etc/protocols: # $Id: x764.php3,v 1.3 2025/02/20 10:59:31 ritter Exp $ # # Internet (IP) protocols # # from: @(#)protocols 5.1 (Berkeley) 4/17/89 # # Updated for NetBSD based on RFC 1340, Assigned Numbers (July 1992). ip 0 IP # internet protocol, pseudo protocol number icmp 1 ICMP # internet control message protocol igmp 2 IGMP # Internet Group Management ggp 3 GGP # gateway-gateway protocol ipencap 4 IP-ENCAP # IP encapsulated in IP (officially ``IP'') st 5 ST # ST datagram mode tcp 6 TCP # transmission control protocol egp 8 EGP # exterior gateway protocol pup 12 PUP # PARC universal packet protocol udp 17 UDP # user datagram protocol hmp 20 HMP # host monitoring protocol xns-idp 22 XNS-IDP # Xerox NS IDP rdp 27 RDP # "reliable datagram" protocol iso-tp4 29 ISO-TP4 # ISO Transport Protocol class 4 xtp 36 XTP # Xpress Tranfer Protocol ddp 37 DDP # Datagram Delivery Protocol idpr-cmtp 39 IDPR-CMTP # IDPR Control Message Transport rspf 73 RSPF # Radio Shortest Path First. vmtp 81 VMTP # Versatile Message Transport ospf 89 OSPFIGP # Open Shortest Path First IGP ipip 94 IPIP # Yet Another IP encapsulation encap 98 ENCAP # Yet Another IP encapsulation

5.9.2. `/etc/networks`

The /etc/networks file has a similar function to that of the /etc/hosts file. It provides a simple database of network names against network addresses. Its format differs in that there may be only two fields per line and that the fields are coded as:

networkname networkaddress

An example might look like:

loopnet 127.0.0.0 localnet 192.168.0.0 amprnet 44.0.0.0

When you use commands like the route command, if a destination is a network and that network has an entry in the /etc/networks file then the route command will display that network name instead of its address.

5.9. Other miscellaneous network related configuration files.

5.9.1. /etc/protocols

5.9.2. /etc/networks

5.9.1. `/etc/protocols`

5.9.2. `/etc/networks`