DHCP Router

[praveen.apr30]

Can we make a Router as a DHCP server.? cn sombody expalin this ?

  What are the challenges will face after configuring it?

Thanks

[Leo Laohoo]

Configuring DHCP

[praveen.apr30]

hi Leo,

i got this, but what am asking is. can a router be DHCP server??

[Leo Laohoo]

What exactly are you trying to do, Praveen?

[praveen.apr30]

Hi Leo,

  I have come across a question asked by my trainer while discussing network concepts.

can a router be a DHCP server? if yes, how the network  traffic will be.since evrytime requests  are being taken care by DHCP server. so i was wondering will it be possible to have a router as a DHCP server.

[Bilal Nawaz]

Hello Praveen, yes we can use a router as a DHCP server.

Please see here: http://www.cisco.com/en/US/docs/ios/12_2/ip/configuration/guide/1cfdhcp.html#wp1000999

The down side I can see is more of an administrative overhead for reserving addresses, you almost have to create a different pool for just one reservation.

To configure a manual binding (static reserved address):

1- Router(config)# ip dhcp pool Client1
2- Router(dhcp-config)# host 192.168.1.101 255.255.255.0
3- Router(dhcp-config)# hardware-address hardware-address type

So long term if you are creating reservations you may want to consider something more user friendly to take the roll of DHCP, but normal options like dns, default gateway, domain name & various hex options or other options can be stated in the pool.

Also like to mention that the DHCP keeps incrementing the addresses given out instead of using the previous address that may be unused.

In other words, instead of giving out .10 which is now a free address, it will give out the next address which might be .21 or something else.

This sometimes is considered a down side but it wouldn't bother me as such. It will use the last available address before going back to what was used previously but is free address. Like a cycle.

Hope this helps

Sent from Cisco Technical Support iPhone App

[cadet alain]

Hi Bilal,

There's a feature called the origin file for static bindings which uses a file with the mappings instaed of configuring multiple host pools.

http://www.cisco.com/en/US/docs/ios-xml/ios/ipaddr_dhcp/configuration/12-4t/config-dhcp-server.html#GUID-BCEB43D4-8C44-4C86-BBAA-6B977196D35C

Regards

Alain

Don't forget to rate helpful posts.

[Bilal Nawaz]

Hello Alain, I did not know this. Thank you for informing me of this method :-)

Please rate useful posts & remember to mark any solved questions as answered. Thank you.

[Peter Paluch]

Hi everyone,

As other friends explained here already, Cisco routers and switches can indeed act as simple DHCP servers, and they are often used for this purpose. However, for more sophisticated deployments including stable IP-to-MAC assignments, I would personally recommend running a standalone DHCP server, e.g. the ISC DHCP server that is better suited than the DHCP server built into the IOS. Nowadays, it is very simple to set up a virtual machine run in VirtualBox, VMWare, Virtual PC - you name it - and run a very simple Linux distribution inside it including all the network services you need, including DHCP.

Best regards,

Peter