Re: Swapping IP address between CPU's

[Philipp Rusch <Philipp.Rusch@xxxxxxxxxxxx>]

One addition:

the AS/400 is quite strannge in behaviour concerning IP-caches:
one thing I know for sure is that even V5R2 machines need to be IPLed (!)
to clear their own ARP-caches. (to resolve other machines)
Maybe there is a PTF to fix this, there should be at least a "clear"-command
for the ARP-table.
When designing hot-swap scenarios you should know about this
ill behaviour, because this fools every switch / router in your network.
Been there, learned it the hard way ... during a long night.

HTH, Philipp Rusch


Philipp Rusch schrieb:

> Rob,
> this *should* be no issue, but you are talking of the ARP cache, where
> mac addresses associated with their resp. IP-addresses.
> This cache can be reset or manipulated through the ARP command,
> Remote manipulation is possible through the means of the ARPING
> command, which can add/modify entries of the ARP cache table.
> I am not shure about the command line parameters, though.
>
> HTH, regards from Germany, Philipp Rusch
>
> rob@xxxxxxxxx schrieb:
>
> > As a poor man's hotsite during our scheduled downtimes we plan on doing
> > the following:
> > ENDTCPIFC INTNETADR('xxx.xxx.xxx.xxx') on the primary iSeries
> > Lock all libraries pertaining to one division.  Save them to a save file.
> > Send them over to our backup.  Verify they've arrived on the backup. Drop
> > the primary.
> > Restore the libraries.  STRTCPIFC INTNETADR('xxx.xxx.xxx.xxx').  Let the
> > user's have their way.
> >
> > However I've been told that the DNS server in our network needs to have
> > it's cache reset to no longer associate that ip address with the old mac
> > address.  Currently that involves telnetting into the router, etc.  I
> > thought about scripting some telnet session, much the same as you can
> > script a ftp session.  Is that possible?
> >
> > Then it was suggested to me that I script a SNMP request.  Evidently they
> > can do more security on that.  And the thought of having router admin
> > passwords buried in script files was not very appealing to them.  I can
> > respect that.  How would one do that from the iSeries?
> >
> > Rob Berendt
> > --
> > "They that can give up essential liberty to obtain a little temporary
> > safety deserve neither liberty nor safety."
> > Benjamin Franklin
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