Messages in this thread | | | Date | Fri, 21 Aug 1998 19:04:48 +0200 (MEST) | From | Roman Drahtmueller <> | Subject | killer |
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Yesterday, 2.1.111 killed a complete ethernet by booting diskless. (!) While retrying rarp and bootp requests, the kernel responded to every single arp request, claiming that the requested ip address belongs to its NIC. (Note: This also happened with rarp turned _off_ in the autoconfiguration section, so only bootp is used. So apparently there is no relation btw the rarp code and this problem. The initial NIC+IP configuration is the matter.) What makes it even worse is that suns under Solaris 2.5.1 as well as 2.6 seemingly have a kernel bug wrt removing arp entries from the cache (arp -d) and setting the arp cache timeout, which means that you either have to down the interface and up it again or reboot the box (ifconfig le0/hme0 down;ifconfig le0/hme0 up apparently fixes the problems), once the "wrong news" has spread over the net. Either way, it may be difficult to get rid of the problem without rebooting all the machines at once (warning).
This is a mess, but one more: the kernel was not instructed via cmdline root=/dev/nfs to boot on an nfs-rootfs. W/o cmdline the kernel is supposed to use a root device which defaults to the one used at compile time. With 2.0, it was necessary to add this parameter to the cmdline for the kernel to activate the network autoconfiguration procedures, "a good idea".
Can somebody please reproduce that? Just compile a kernel with network autoconfiguration turned on and a NIC driver for an attached NIC built into the kernel, dump it to a diskette and boot it, without some configuration elsewhere to catch the requests (let it time out and watch what happens). You might not want to try this in a production environment, even though it's funny. Prepare all other boxes to delete the arp caches. The relevant code hasn't been changed (significantly) during the last versions of 2.1.x.
Discovered by poor Martin Walter, CC univ. o. Freiburg. :-)
Roman. Computer Center University of Freiburg, Germany. "The whole world is about three drinks behind." (Humphrey Bogart)
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