DHCP Not Handing Out IP Addresses
Articles and Tips: qna
01 Mar 2003
Q.
I have just recently set up a new server using Broadcom Engineering's LAN driver. The funny thing is that once the Dynamic Host Configuration Protocol (DHCP) has been configured, it does not hand out any IP addresses as clients authenticate. What could be my problem?
I am using Novell NetWare 6 Support Pack 2. The Broadcom LAN driver is B57.LAN Version 2.3232 that is dated May 7, 2002.
No Handouts in Houston
A.
Dear No Handouts: I get off easy on this one. I have a contact who has already talked with Broadcom Engineering. He found out that there are a couple of problems here. They both funnel down to causing DHCP to not hand out IP Addresses. The first affects the B57.LAN and Q57.LAN drivers, as they are not correctly signing the User Datagram Protocol (UDP) checksums. The second involves the B57.LAN and Q57.LAN hardware cards; they are issuing duplicate Media Access Control (MAC) addresses.
First let's discuss the causes of these two problems, then I will provide you with a fix.
MAC Address issue: On some servers (i.e. yours) that are using the B57/Q57 LAN cards, there is a timing problem that can cause problems reading the MAC address from the firmware. This causes the card to use a default MAC address. Unfortunately, this duplication issue arises when more than one card is used in the same segment of your network.
UDP Checksum issue: In both NetWare 5 Support Pack 5 and NetWare 6 Support Pack 2, Novell corrected a problem with UDP checksums in the TCP/IP stacks for NetWare. Since the Broadcom driver you are using was written to work around the faulty behavior of the older TCP/IP stack, Novell fixing the TCP/IP stack broke the B57.LAN and Q57.LAN drivers. Of special note is that this problem specifically affects the DHCP Server, the DNS Server and any other UDP-based service that the server may be providing.
Now the most important part--and I'm sure the part what you have been waiting for--here's the fix! Like the problems discussed above, this will be handled in a two-part fashion.
MAC Address issue: The current workaround is to force the MAC address to be overridden with a statically defined IP address. (Novell recommends that you consult the IEEE website to select an appropriate range of addresses for your server/LAN card. Then check to make sure that this MAC address doesn't exist elsewhere in your organization. Once you have selected a MAC address, you will need to use the command line overider argument of "node=XXXXXXX."
UDP Checksum issue: You will need to disable UDP checksumming. This can only be done on the hardware LAN card. You can disable UDP checksumming on the hardware LAN card by adding the CHECKSUM=OFF flag to the end of the first load line of the B57.LAN driver. This is what it would look like in your AUTOEXEC.NCF file:
LOAD B57.LAN BOARD=<BOARD NAME> SLOT=<SLOT NUMBER> CHECKSUM=OFF
BOARD NAME and SLOT NUMBER should be set to appropriate values.
If you are using INETCFG.NLM for you LAN configuration, then you will need to manually edit the LOAD line in the NETINFO.CFG file. If you choose to do this, make sure that you modify the NETINFO.CHK file and change the value to 0; otherwise, INETCFG will consider the NETINFO.CFG to be corrupt.
Lastly, Broadcom Engineering has been notified of this problem by Novell Technical Support.
* Originally published in Novell AppNotes
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The origin of this information may be internal or external to Novell. While Novell makes all reasonable efforts to verify this information, Novell does not make explicit or implied claims to its validity.