Excluding a range from a subnet
John Hascall
john at iastate.edu
Wed Apr 23 11:35:08 UTC 2008
> I have to add a dhcp server in an already configured subnet, and manage
> a range. The problem is that in my range, there may be one or many
> devices with a static ip not configured in dhcp, and my dhcp server
> musn't manage them. I'd like to declare one range, with excluded
> ip/ranges to ignore. I had a look on internet but didn't find smthg
> corresponding exactly to what I need :
[manually abandon the addresses in the lease file]
This will surely bite you some day in the future.
> Segmenting my range :
This is what you need to do.
It is not that hard or inelegant. For example:
shared-network "sample" {
subnet 192.168.117.0 netmask 255.255.255.0 {
option broadcast-address 192.168.117.255;
option routers 192.168.117.254;
...
}
# we always reserve 0, 250-255
# 15, 42-49, 51-56, 61 are not managed by dhcp
pool {
range 192.168.117.1 192.168.117.14;
range 192.168.117.16 192.168.117.41;
range 192.168.117.50;
range 192.168.117.57 192.168.117.60;
range 192.168.117.62 192.168.117.249;
...
}
}
> Declaring them as hosts :
Given a new enough version of dhcpd you can apparently 'reserve'
the in use addresses in th erange to the existing devices. I
have not tried this myself.
John
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