diff -ur linux-2.4.19/Documentation/filesystems/proc.txt linux-2.4.19.new/Documentation/filesystems/proc.txt
--- linux-2.4.19/Documentation/filesystems/proc.txt	Wed Nov  7 23:39:36 2001
+++ linux-2.4.19.new/Documentation/filesystems/proc.txt	Sun Nov 10 13:09:25 2002
@@ -1592,10 +1592,32 @@
 error_burst and error_cost
 --------------------------
 
-These parameters  are used to limit the warning messages written to the kernel
-log from  the  routing  code.  The  higher the error_cost factor is, the fewer
-messages will  be written. Error_burst controls when messages will be dropped.
-The default settings limit warning messages to one every five seconds.
+These  parameters  are used to limit how many ICMP destination unreachable to 
+send  from  the  host  in question. ICMP destination unreachable messages are
+sent through the code controlled by these parameters in three events:
+
+1. We can not reach the nexthop.
+2. We have no route set up for the network segment or host.
+3. We have a routing rule or route set to unreachable, throw or prohibit.
+
+The  networking code in question then sends out ICMP destination unreachables
+with three different codes if necessary:
+
+1. ICMP  host  unreachable in case the host should be directly connected to a 
+   network  we  are  part  of, or if the host was set to unreachable or throw
+   through a rule or route.
+2. ICMP  network  unreachable  if  we do not know how to reach the network in 
+   question,  or  if  the  network  was set to unreachable or throw through a 
+   rule or route.
+3. ICMP  communication administratively prohibited by filtering is sent if we 
+   have a rule or route set to prohibit.
+
+It  will also print some error messages to kernel logs if someone is ignoring 
+our   ICMP  redirects.  The  higher  the  error_cost  factor  is,  the  fewer 
+destination  unreachable  and error messages will be let through. Error_burst 
+controls  when  destination  unreachable  messages and error messages will be
+dropped. The default settings limit warning messages and log messages to five
+every second.
 
 flush
 -----