2011-04-29 08:43:18     set up isc-dhcpd server on blackfin uClinux

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2011-04-29 08:43:18     set up isc-dhcpd server on blackfin uClinux

Sebastian Heinrich (GERMANY)

Message: 100294   




I have a problem setting up the dhcpd server under uClinux on BF537 (CM-BF537E).


The compilation (uClinux - Release 2009, please note that it is not in my hands to switch to the 2010 release) seems to go through well, and starting dhcpd makes:


dhcpd -q -lf /tmp/dhcpd.leases


Listening on LPF/eth/0/de:6d:ff:56:73/


Sending on  LPF/eth/0/de:6d:ff:56:73/


Sending on Socket/fallback/fallback-net




Then the output stops and nothing happens. If I try to get an IP-Adress with my ubuntu laptop the dhcp-client fails.


My dhcpd.conf file:




#ddns-update-style none;




#option domain-name-servers,;




default-lease-time 86400;


max-lease-time 604800;








subnet netmask {




        option subnet-mask;


        option broadcast-address;


        option routers;






the uClinux boots from a flash disk. Therefore the filesystem is not writeable and I give dhcpd the parameter -lf /tmp/dhcpd.leases. /tmp is a ramdisk. So dhcpd will lose its leases after a reset but that doesn't matter.


Ah, bevore I start dhcpd a set my own IP-Adress with ifconfig to with netmask


The environment is Laptop->Switch->Blackfin Board. Because of my predecessor I have to made a ethtool -s eth0 speed 100 duplex half autoneg off bevore starting dhcpd.


Strange is, that if I uncomment the #ddns-update-style none; then dhcpd's output is  "configuration file errors encountered -- exiting".


Has anybody an idea what goes wrong or what I have configured false?




Thanks for help.













2011-04-29 14:11:15     Re: set up isc-dhcpd server on blackfin uClinux

Mike Frysinger (UNITED STATES)

Message: 100297   


ISC's dhcpd is pretty fat.  have you tried busybox's udhcpd instead ?




2011-04-30 06:17:40     Re: set up isc-dhcpd server on blackfin uClinux

Sebastian Heinrich (GERMANY)

Message: 100322   


Yes I have.


But it  causes a Null Pointer Exception every time I start it.


Honestly I was too lazy to search for the reason of this error :-)


Do you have an idea what problem the dhcpd might have ? I know that my question is very generally and it could might have several reasons. But I postet this question for the reason that I might have done a realy stupid mistake, that could be solved easily. If not, I will give udhcpd another chance.


Is this problem I have with udhcpd well-known? It seems to compile without any error and crashes every time I start.


I know that you will tell me to switch to realse of 2010 of uClinux. But unfortunately is that not in my hands.


On monday I'm able to post the output of udhcpd (stack trace, ..) if that might help.


Do you need more information ? Did I forgot something important ?




Have a nice weekend.








2011-05-02 08:11:49     Re: set up isc-dhcpd server on blackfin uClinux

Sebastian Heinrich (GERMANY)

Message: 100339   


I didn't find out the reason dhcpd is not working.


But with the right configuration for the udhcpd.leases file (the directory was wrong) udhcpd works fine.


Thanks for helping me!