DNSMasq as DHCP server

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Revision as of 12:54, 12 February 2006 by Cyberde (Talk | contribs)
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Contents


Introduction

DD-WRT supports DNSMasq "as local DNS server" and uses for the DHCP service additionally "udhcpd". This is a waste of the RAM (router has only 16MB and 3MB free). With DNSMasq as DHCP server you can save 300kb (udhcpd deactivated!). With this savings you can create one PPTP tunnel more with the inserted PPTPD server.


There are two ways to accomplish this

  • Using the Web-Interface
  • Using DMSMasq parameters

You can NOT use both ways


Setting it up

Using Web-Admin

This is the easiest way to setup DNSMasq as DHCP Server


  • Go to your Web-Interfaceand log in
  • Go to Setup->Basic Setup
    • Make sure that
      • DHCP Type = DHCP Server
      • DHCP Server = enabled
      • Use DNSMasq for DHCP = checked


Image:Setup_basic_dhcp.jpg


  • Go to Administration->Services
    • Make sure that
      • DHCP Daemon = enabled
  • You can add static allocations the same way when you're using DHCPd


Image:Administration_services_dhcpd.jpg


Using DNSMasq parameters

Following steps are necessary:

  • deactivate the DHCPD service on the "Setup" page.
  • add in the options of the DNSMasq under "administration" (this must be also activated):
dhcp-range=192.168.0.100,192.168.0.150,255.255.255.0,12h 


Static allocation:

dhcp-host=AB:CD:EF:11:22:33,192.168.0.10,host,host.domain,12h  


AB:CD:EF:11:22:33 is the MAC of the network, 192.168.0.10 will indicate the desired IP, host and host.domain the hostname (e.g. Computer1.lan) and finally 12h the DHCP release of 12 hours.

If you want to identify devices via name resolution and it's not possible to assign an IP with DNSMasq you must add the following lines:

no-hosts
add-hosts=/tmp/hosts 

You must also add this computer to the /tmp/hosts:

192.168.0.5 printers drucker.lan 


Original Thread: http://blog.ptch.de/index.php?/archives/33-WRT54G-DNSMasq-als-DHCPD.html (german)


Extra DNSMasq options

There are some extra options you can set by entering them in Additional DHCPD Options


ISP DNS-Servers

If you wish to passthru the DNS-Servers from your ISP, you can use the folowing parameters:

dhcp-option=6,x.x.x.x,y.y.y.y

x.x.x.x = DNS1
y.y.y.y = DNS2


Never offer DHCP service to specific MAC-Addresses

You can ignore request from specific MAC-Addresses, so no IP-Address will be leased to that machine

dhcp-host=11:22:33:44:55:66,ignore

11:22:33:44:55:66 = MAC-Address of the machine you wish to ignore


For more options take a look at http://www.faqs.org/rfcs/rfc2132.html