[comp.unix.aix] strange tcpip problem: SOLVED!!

eliot@engr.washington.edu (Eliot Lim) (06/13/91)

First of all, many thanks to everyone for their suggestions; including IBM.
I still don't know what got screwed up but it doesn't matter.  What I did
was to open up the covers and move the ethernet card to another slot.

I don't know if this is a bug or a feature, but if you move your ethernet
card, the OS will assign it a new hardware address and leave the old one
and treat it as a device that has gone offline.  So with a "new" device
I was able to configure it from scratch and it came right up!


Eliot


p.s. be sure to insulate yourself properly from static before trying this.

drake@drake.almaden.ibm.com (06/13/91)

In article <1991Jun12.230426.22643@milton.u.washington.edu> eliot@engr.washington.edu (Eliot Lim) writes:
>I don't know if this is a bug or a feature, but if you move your ethernet
>card, the OS will assign it a new hardware address and leave the old one
>and treat it as a device that has gone offline.  

Feature.  How else could it work?  Consider a scenario ...

Machine has two Ethernet adapters, one in slot 3 attached to network A,
and one in slot 4 attached to network B.  Lightning strikes and the
adapter in slot 3 goes "poof".

Now, when the machine comes up, I really want it to remember that the
slot 4 Ethernet card is on network B, not go playing guessing games.
Any method that didn't make the adapter definitions slot dependent
would cause icky problems in such scenarios...you'd wind up with an
adapter on network B, perhaps with a definition for network A ... total
chaos.  Similarly (and identically from the software's viewpoint),
pulling out the slot 3 card shouldn't screw up the connection to
network B.

SO, the moral is that while all slots are created equally, the slot
address of a card is just as important and unchangeable as the SCSI
address of a drive.

How do other systems handle this?


Sam Drake / IBM Almaden Research Center 
Internet:  drake@ibm.com            BITNET:  DRAKE at ALMADEN
Usenet:    ...!uunet!ibmarc!drake   Phone:   (408) 927-1861

karish@mindcraft.com (Chuck Karish) (06/14/91)

In article <843@rufus.UUCP> drake@drake.almaden.ibm.com writes:
|In article <1991Jun12.230426.22643@milton.u.washington.edu>
|eliot@engr.washington.edu (Eliot Lim) writes:
||I don't know if this is a bug or a feature, but if you move your ethernet
||card, the OS will assign it a new hardware address and leave the old one
||and treat it as a device that has gone offline.  
|
|Feature.  How else could it work?  Consider a scenario ...
|
|Now, when the machine comes up, I really want it to remember that the
|slot 4 Ethernet card is on network B, not go playing guessing games.
|Any method that didn't make the adapter definitions slot dependent
|would cause icky problems in such scenarios...
|
|How do other systems handle this?

Record the cards' Ethernet ID numbers, and query them at boot time?
-- 

	Chuck Karish		karish@mindcraft.com
	Mindcraft, Inc.		(415) 323-9000

drake@drake.almaden.ibm.com (06/14/91)

In article <676836895.5438@mindcraft.com> karish@mindcraft.com (Chuck Karish) writes:
>
>Record the cards' Ethernet ID numbers, and query them at boot time?

That's another obvious approach ... which leads to similar surprises as
the slot-based method.  With the Ethernet-ID approach you can indeed move
the cards around from slot to slot, but you can't replace a broken card
with a new card without reconfiguring the software.  


Sam Drake / IBM Almaden Research Center 
Internet:  drake@ibm.com            BITNET:  DRAKE at ALMADEN
Usenet:    ...!uunet!ibmarc!drake   Phone:   (408) 927-1861