Network Configuration- OpenBSD

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OPENBSD NOTES: Basic Network Configuration         AUG 2005

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REFERENCE: Identify the key files:

text config files

 /etc/hostname.neX                    <- one of these for each nic
 /etc/mygate                          <- default route
 /etc/resolv.conf                     <- dns server resolution

ifconfig: bring up or down an interface

 ifconfig ${DEVICE} down

 ex: ifconfig ne0 down

Dynamic Host Configuration Protocol (DHCP)

To get OpenBSD to auto start dhclient on boot edit /etc/hostname.neX like this:

 echo dhcp > /etc/hostname.neX

Basically, the configuration file for your network IP addressing information is in the /etc directory and begins with 'hostname.' followed by the name of the Ethernet interface. The following is the correct syntax for this file:

 dhcp NONE NONE NONE

start a DHCP client from the command line

 dhclient neX

Static IP address configuration

To configure the system for a static IP address, enter the IP address, subnet mask, and the rest in the /etc/hostname.neX file:

 192.168.0.5 255.255.255.0 NONE NONE

Change IP address on running machine w/o reboot

Unlinke linux, there are no network script frontends for ifconfig. Use ifconfig to change the IP address for a given interface.

 ifconfig neX inet 10.10.192.5 netmask 255.255.255.224

Default route or Gateway IP address

The default route, or 'gateway' address needs to go in a file inside the /etc directory called 'mygate'. The file may not exist on a default install.

 touch /etc/mygate

Populate it with the IP address for the default route.

 192.160.0.1

Change the default route on running machine w/o reboot

first, remove the old route

 route del -net 169.254.0.0 netmask 255.255.0.0 gw 0.0.0.0 dev eth0

or if you prefer, flush them all out

 route flush

now add the new default route (gateway) for the machine

 route add default 10.10.192.1

DNS configuration

Place the DNS server information in /etc/resolv.conf

 nameserver 64.21.192.4
 nameserver 10.10.0.13
 lookup file bind

hostname configuration

The hostname for the machine, or host and domain is in the plain text file:

 /etc/myname

Change the hostname on running machine w/o reboot

Just use the hostname command

 hostname myhost.domain.com