DHCP bindings database....

uubozou11 · ‎11-26-2007

What is the point of a DHCP bindings database? I have read all of the cisco docs, and all it says is that its used to keep track of IP assignments in case the router bombs and you need to give out IPs...or something like that. Is it very critical to have?

Thanks

williamsdo · ‎11-26-2007

Hi, DHCP binding is a list of lease assignments of your DHCP server you are correct. Since DHCP is dynamic you can cofigurer the server to limit the time that leases are allowed, you can also use manual binding for printers and other devices that need to keep their IP address for long leases. One good use for the database is if you need to release IP addresses you can do it from you server and not from the local workstation can save you some shoe leather. have a look at the link below for more information. To answer your question yes I would keep the database.

http://www.juniper.net/techpubs/software/erx/junose80/sw-rn-erx801/html/sw-rn-erx801-app-dhcp-bindings.html

ymj · ‎12-05-2007

Hello,

If you want to release a lease you should (must) do it from the client otherwise you lose the whole point of having a DHCP database --> it should be consistent with reality.

If you clear the lease without actually releasing it on the workstation, you'll end up with address conflicts or so-called Unavailables. Indeed, by default the DHCP server pings the address it's about to give away to check whether it's already (mis)used by something else, if yes it puts in into the Unavaible state (CNR) or conflict table (IOS).

If this feature is disabled you risk to get duplicate IP addresses.

The actual "database" feature is used to saved the DB on a FTP / TFTP /RPC repository on a regular basis. Actually the DB disapears upon reboot which can lead to address conflicts, etc...

Now what I'm wondering is whether it is also fetched on the FTP/TFTP server after reboot ?

I'm going to test but if you know anything please let us know