Bug 14933 - Linuconf segfaults with emty subnet entry in dhcp.conf
Linuconf segfaults with emty subnet entry in dhcp.conf
Product: Red Hat Linux
Classification: Retired
Component: linuxconf (Show other bugs)
i386 Linux
medium Severity medium
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Assigned To: Nalin Dahyabhai
Depends On:
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Reported: 2000-07-31 18:32 EDT by dbelliz
Modified: 2008-05-01 11:37 EDT (History)
0 users

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Fixed In Version:
Doc Type: Bug Fix
Doc Text:
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Clone Of:
Last Closed: 2000-08-21 21:50:22 EDT
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Description dbelliz 2000-07-31 18:32:35 EDT
My DSL provider has given me a stub network with a netmask of /30. Since
both valid addresses are already taken by my DSL router and my dhcp server,
there are no free addresses to assign to a range.  

Dhcpd fails to start with 

Internet Software Consortium DHCP Server 2.0
No subnet declaration for eth0 (
Please write a subnet declaration for the network segment to
which interface eth0 is attached.

if the there isn't a subnet entry in /etc/dhcp.conf like

subnet netmask{

Linuxconf however will not let me assign a dhcp subnet with a range of 0. 

If I manually edit the file and put the above subnet entry in the
/etc/dhcp.conf linuxconf will allways segfault.  

This is reproducable with 

Comment 1 Larry Adams 2000-08-21 21:50:18 EDT
I have a similar problem.  I have a subnet mask of  When I 
setup the network settings below and then run "netstat -nr" I receive invalid 
information and routing outside the subnet does not work.

IP Address:

netstat -nr reports

IP Address:
Genmask: (What's This Netmask ??????)
IP Address:  (This IP Address does not exist on the Network)
Genmask: (Should have been assigned to 138 above)

I am screwed!  Can not make networking work.

Comment 2 Nalin Dahyabhai 2000-09-12 15:50:37 EDT
A range cannot have zero addresses.  If you mean to not have
dynamically-allocated addresses, just omit the range altogether.  If you want to
assign one address dynamically, then it is both the upper and lower bound of the
range you want to make available, so use either 1 address or specifiy the same
number for both the beginning and end of the range.

Larry, your problem is different.  With and IP of and a netmask
of, your gateway cannot be anything outside the range to, so you've been given bad data.  The first line
from netstat is the address of your interface, the second is the network of
addresses that its interface and netmask show would be "local", and can
therefore be reached without having to go through a gateway.
Comment 3 dbelliz 2000-09-12 21:33:36 EDT
Pardon me but, thats bull.  All I was asking for is the same functionality with
linuxconf as with manual configuration. If I can specify a blank range (a range
of zero addresses or how ever you want to say it) with the following in the
dhcpd.conf file, why then can't I do it with linuxconf. 

subnet netmask{

My bug is still valid. If you manually configure dhcpd.conf with above and run
linuxconf with the dhcpd module active it will segfault.  

I can't see why you labeled it as not a bug when it's completely reproduceable.

You say to "just omit the range altogether" linuxconf will not let you do this. 
have you tried to repro the problem or are you just cleaning old bugs?

Comment 4 Ken 2000-10-01 01:00:54 EDT
dbellize is right.  If I have a subnet {} statement with nothing inside, or in
my case just 'option netmask;' within, Linuxconf crashes, and
dumps core.

Once I commented out the 'offending' subnet statement, Linuxconf works.  This is
a bug with Linuxconf, not dhcpd (since it functions fine with the statement in)


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