Hitchhiker's Guide to Openbsd

6.4.2 - DHCP Server
If you want to use OpenBSD as a DHCP server 
dhcpd(8)
, edit 
/etc/rc.conf.local
so that it 
contains the line 
dhcpd_flags="interface"
, replacing 
interface
with the list of interfaces 
that dhcpd(8) should listen on, for example: 
# echo 'dhcpd_flags="xl1 xl2 xl3"' >>/etc/rc.conf.local
Then, edit 
/etc/dhcpd.conf
. The options are pretty self-explanatory. 
option domain-name "example.com";
option domain-name-servers 192.168.1.3, 192.168.1.5;
subnet 192.168.1.0 netmask 255.255.255.0 {
option routers 192.168.1.1;
range 192.168.1.32 192.168.1.127;
}
This will tell your DHCP clients that the domain to append to DNS requests is example.com (so, if the 
user types in 'telnet joe' then it will send them to joe.example.com). It will point them to DNS servers 
192.168.1.3 and 192.168.1.5. For hosts that are on the same network as an Ethernet interface on the 
OpenBSD machine, which is in the 192.168.1.0/24 range, it will assign them an IP address between 
192.168.1.32 and 192.168.1.127. It will set their default gateway as 192.168.1.1. 
If you want to start dhcpd(8) from the command line, after editing 
/etc/dhcpd.conf
, try: 
# touch /var/db/dhcpd.leases
# dhcpd fxp0
The 
touch
line is needed to create an empty 
dhcpd.leases
file before dhcpd(8) can start. The 
OpenBSD 
startup scripts
 will create this file if needed on boot, but if you are starting dhcpd(8) 
manually, you must create it first. 
fxp0
is an interface that you want to start serving DHCP on. 
http://www.openbsd.org/faq/faq6.html (11 of 33)9/4/2011 10:02:06 AM

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6 - Networking
If you are serving DHCP to a Windows box, you may want dhcpd(8) to give the client a 'WINS' server 
address. To make this happen, just add the following line to your 
/etc/dhcpd.conf
: 
option netbios-name-servers 192.168.92.55;
(where 
192.168.92.55
 is the IP of your Windows or Samba server.) See 
dhcp-options(5)
 for more 
options that your DHCP clients may want. 
6.5 - PPP 
The Point to Point Protocol (PPP) is generally what is used to create a connection to your ISP via a dial-
up modem. OpenBSD has 2 ways of doing this: 
●
pppd(8)
- the kernel PPP daemon 
●
ppp(8)
 - the userland PPP daemon 
Both ppp and pppd perform similar functions, in different ways. pppd works with the kernel 
ppp(4)
 
driver, whereas ppp works in userland with 
tun(4)
. This document will cover only the userland PPP 
daemon, since it is easier to debug and to interact with. To start off you will need some simple 
information about your ISP. Here is a list of helpful information that you will need. 
●
Your ISP's dial-up number 
●
Your nameserver 
●
Your username and password 
●
Your gateway 
Some of these you can do without, but would be helpful in setting up ppp. The userland PPP daemon 
uses the file 
/etc/ppp/ppp.conf
as its configuration file. There are many helpful files in /etc/ppp that can 
have different setups for many different situations. You should take a browse through that directory.