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Old 12-19-2004, 04:23 PM   #1
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DHCP: Bad subnet number/mask combination

Hello. I´m new to linux and I would like to configure my network. I have two PCs (server ¨olixnet¨ running Mandrake 10.1 - connected to intenet via ethernet card eth0 and to a laptop ¨kvakos¨ running Windows XP via eth1). This is a topology:


Both ethernet adapters on olixnet have the same ip - Everything works fine but the DHCP. When I try to start DHCP, it writes ¨bad subnet number/mask combination. subnet netmask¨
This is my dhcpd.conf file:

ddns-update-style none;
subnet netmask {
# default gateway
option routers;
option subnet-mask;
range dynamic-bootp;
default-lease-time 21600;
max-lease-time 43200;
When I change netmask to it works but I need to leave it It worked on Mandrake 9. Please tell me how to make it work properly. Thanx.
Old 12-19-2004, 06:03 PM   #2
Registered: Nov 2004
Location: Brisbane, Australia
Distribution: Fedora Core 5
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Originally posted by OliXNet
Both ethernet adapters on olixnet have the same ip -
You need to assign different IP addresses to each network device, they can not be the same.

Also, you haven't specified a range of IPs to lease for your workstations (only bootp).
ipcalc -n -m
Also your is not a valid network address for that subnet., that's why /24 worked ok.

Here's a howto if you need it:

Old 12-20-2004, 10:32 AM   #3
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thank you very much... but... I´ve configured eth1 to IP, then DHCP subnet IP to and successfully started DHCP server. I´ve tried ipconfig /renew on WinXP and it works properly... The only problem is that I can´t ping the linux machine. ping even doesn´t work... I know it is probably stupid problem, but remember I am very new to Linux.. So, please be patient
Old 01-07-2010, 10:04 AM   #4
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Question bad subnet/number mask combination

Hi,I use following commands in dhcpd.conf and get the subnet number/mask combination err.please help me

subnet netmask {

what is my problem ?
Old 01-07-2010, 10:17 AM   #5
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This thread is 4 years old, you might be better off starting a new thread in the appropriate forum.


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