Re: Can someone explain this?

[Vern Hamberg <vhamberg@xxxxxxxxxxx>]

Cool! I'm glad I asked, because I learned something new today - and we 
have the info in the archives, too.

Vern

On 4/14/2011 10:16 AM, Dennis wrote:
> I specified linux world because I have deep administrative experience there.  (Also with i, though I've not been blessed with this opportunity on that platform.  Also because unix administrators _tend_to_be_ more TCP savvy.  I did not mean to imply that this relates only to *ix.  Quite the opposite, actually.
>
> Even (gasp!) on mafinframe, this is an issue, because the problem is at the root of all TCP communications, not imbedded in some system's O/S code.
>
> "Vern Hamberg"<vhamberg@xxxxxxxxxxx>  wrote:
>
> > The trouble with this, Dennis, so far as I can see, is that this box
> > isn't UNIX - we have never had to think about clearing ARP on this box.
> >
> > I don't know if there is even a way to do it.
> >
> > Perhaps that is accomplished by the system when restarting TCPIP -
> > maybe
> > with some other command.
> >
> > This system, as you know, is positioned as not needing all that
> > administrative stuff other OS' do.
> >
> > So is there a way to clear the ARP? It'd be an interesting thing to
> > know.
> >
> > Thanks
> > Vern
> >
> > On 4/14/2011 9:13 AM, Dennis wrote:
> > > It is a general rule-of-thumb in the unix world: If you replace a
> > switch, clear ARP.  If you replace a router, clear ARP.  Seems to avoid
> > a wealth of issues.
> > > "Gqcy"<gmufasa01@xxxxxxxxx>   wrote:
> > >
> > > > On 4/14/2011 7:43 AM, Don Cavaiani wrote:
> > > > > Last night we put in all new switches, and quickly replugged the
> > IBM
> > > > i
> > > > > Ethernet cable, and the system went on running, telnet for sure.
> > > > >
> > > > > However, the http servers no longer connected.  This morning I
> > > > > re-started all the HTTP servers, but we were still unable to
> > connect.
> > > > > I then did an IPL which brought everything back up.
> > > > In my experience, _every_time_ we unplug the Ethernet cable, we had
> > > > to at a minimum end and restart TCP/IP, and sometimes vary off and
> > on
> > > > the controller...
> > > > ymmv...
> > > >
> > > > -gerald
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