[prev in list] [next in list] [prev in thread] [next in thread] 

List:       dhcp-users
Subject:    Re: dhcp-server subnet configuration for interfaces not being listened to
From:       "Simon Hobson"  <dhcp1 () thehobsons ! co ! uk>
Date:       2013-03-18 12:18:37
Message-ID: 090F176862479D0ECE9C98F12550CBC6 () thehobsons ! co ! uk
[Download RAW message or body]

Amir Sagie wrote:
> I've recently been using isc-dhcp-server v4.2.4 on a box with multiple
> network interfaces and noticed that it will happily accept subnet
> configurations which are bound to interfaces on which dhcpd is not
> configured to run. Example:
> 
> # dhcpd -t -cf /etc/dhcpd.conf eth1
> 
> where /etc/dhcpd.conf includes:
> 
> subnet 192.168.1.0 netmask 255.255.255.0 { ... }
> subnet 192.168.2.0 netmask 255.255.255.0 { ... }
> 
> Assuming eth1, eth2 are bound to 192.168.1.0/24, 192.168.1.0/24
> respectively, dhcpd issues no warning when eth2 is omitted from the
> daemon launch command, nor does is log "dropped" DHCP discover messages.
> I am aware that interfaces are expected to come & go and their addresses
> to change, but in more static environments I think a log warning (upon
> daemon launch) is called for, eg:

How does the DHCP server know that those subnets aren't actually being used ?
While it's somewhat contrived, it's perfectly possible that there is a relay agent \
involved, and the server is actually servicing those subnets - just not directly.

In general, it's expected that the administrator knows what he's doing. The ISC \
server supports some incredibly flexible setups, and it's impossible for the parser \
to test all combinations. _______________________________________________
dhcp-users mailing list
dhcp-users@lists.isc.org
https://lists.isc.org/mailman/listinfo/dhcp-users


[prev in list] [next in list] [prev in thread] [next in thread]