On Friday, 08/25/2006 at 12:48 MST, "Stricklin, Raymond J" <[EMAIL PROTECTED]> wrote: > For the benefit of the rest of the list; > > Alan's suggestion to enable faked frame headers solved the problem I was > having. > > Unfortunately, a second problem surfaced immediately. The VSWITCH would > give me an error when the DHCP client received its lease: > > HCPSWU2833E Error 'E00A'X adding IP address 192.54.6.16 for VSWITCH > SYSTEM VLINUX1. > HCPSWU2833E IP address is already in use on the LAN.
...snip... > We've been using IP VSWITCH without DHCP for about a year, > and why we never ran into this problem before, I couldn't exactly say. Did you perhaps change the client from SLES9 to SLES10 in the process? Somewhere along the way, Linux (dhclient?) changed to issue a gratuitous ARP *before* it registers the IP address in the OSA. Of course, the registration of an IP address in a Layer 3 OSA causes it to see if the IP address is already used. WHAM! You hit the ARP cache entry created by the "manual" grat ARP. Or Linux has always done that but timings have changed sufficiently to finally surface the problem. (A gratuitous ARP is what we call an unsolicited response to an ARP query.) It doesn't make sense for Linux to send a grat ARP before it has finished configuring the interface. In fact, I would think that would be a function of interface configuration itself, left to the device driver itself. Or maybe something's broken. It works with Layer 2 because the OSA doesn't do any automatic grat ARPs. <Chuckie> I think the problem *could* be mitigated by the OSA itself. OSA could allow an IP address to be registered if the grat ARP was received on a data channel associated with the control channel over which the IP address is being registered. Of course, the h/w guys would say that just disabling the grat ARP (ARP=no) makes the problem go away and that's sufficient. I'm also of the opinion that the *applications* should not have to change to accomodate this odd behavior of the Layer 3 OSA. But, then, my nickname is "Mr. Quixotehead". AND, the fix really does be in Lniux itself. </Chuckie> Alan Altmark z/VM Development IBM Endicott ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390
