Bootp Timeout Problem

Date: Mon Oct 15 2001 - 12:05:30 EST

Lars - I came across the message below while searching to a solution for a
DHCP timeout issue. I'm fairly certain that this fix is relevant to the
problem I'm investigating. We're working with a floppy linux distro that
Novell created for imaging Novell workstations and I hope to apply this
patch to the floppy distro to see if it is the fix we're looking for (we
suspect Spantree Portfast on Cisco Catalyst3524XLs is tripping up DHCP

I'm a bit of a linux newbie - does this involve editing the ifconfig.c file
only, or is a recompile or any components (or even the kernel?) required
to cause the change to take effect? If so, I expect the various FAQs can
walk me through the actual procedure.

LKML - apologies if this is off-topic, please reply off-list or CC me.

thanks much,
-carl hirsch
network analyst

From: Lars Magne Ingebrigtsen (
Date: Sat Jul 29 2000 - 06:16:33 EST
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The Cisco Catalyst 3500 switch has what seems like a training period
of about ten seconds. Therefore, the default 3*2 second waiting
period between card resets is too small to allow a Linux bootp client
to boot through one of these switches.

The following micro-patch just increases the CONF_SEND_RETRIES (which
says how many bootp packets to send out between reopening the device(s))
from 3 to 10, which fixes the problem.

--- ipconfig.c~ Wed Jun 7 23:26:44 2000
+++ ipconfig.c Sat Jul 29 12:53:18 2000
@@ -75,7 +75,7 @@

 /* Define the timeout for waiting for a DHCP/BOOTP/RARP reply */
 #define CONF_OPEN_RETRIES 3 /* (Re)open devices three times */
-#define CONF_SEND_RETRIES 3 /* Send requests three times */
+#define CONF_SEND_RETRIES 10 /* Send requests ten times */
 #define CONF_BASE_TIMEOUT (HZ*2) /* Initial timeout: 2 seconds */
 #define CONF_TIMEOUT_RANDOM (HZ) /* Maximum amount of randomization */
 #define CONF_TIMEOUT_MULT *7/4 /* Rate of timeout growth */

(domestic pets only, the antidote for overdose, milk.) * Lars Magne Ingebrigtsen

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