Re: Can someone explain this?

[Dennis <iseries@xxxxxxxxxxxx>]

Sorry, I misread your message.  While it is true that TELNET and HTTP should be impacted equally, there is the assumption that they are using like routes (single network interface).  I don't know that that is accurate.

"DrFranken" <midrange@xxxxxxxxxxxx> wrote:

> First of you should certainly have the CMNRCYLMT on your ETHERNET lines
>
> set to (1 0) to allow infinite retries.  ALL Y'ALL should be doing this
>
> in fact.
>
> Well I don't think it was ARP on the i unless you use different IP 
> Addresses for the HTTP servers than for Telnet. There is a one to one 
> relationship between ARP entries and IP Addresses so you can't mess up 
> the HTTP ARP entry and not the TELNET ARP entry as they would be the
> same.
>
> In addition to that if you think about it, the ARP entries ON the i 
> would be for itself but also for anything it's talking to. Neither the
> i 
> nor the servers or clients it was talking to would have gotten a new
> ARP 
> entry.  Only the switches changed. So lets look at the switches.
>
> Switches have ARP tables too, in fact theirs are VERY important. When 
> you pulled out the cable and moved it to the new switch it's not the
> ARP 
> table on the i that had a problem, it's entries were still correct. The
>
> switches in the network however may very well have though the i was 
> still where it was before - on the old switch. Hence traffic to it
> might 
> still have been directed there and that switch, no longer able to 
> communicate with it, simply dropped the packets. So the correct
> solution 
> was to clear the ARP entries on the switches.
>
> Depending on the switch brand you can clear those tables from command 
> lines. You can always reboot them (not a pretty option.)   IPLing the i
>
> accomplished the task in a rather brute force way because when it came 
> back up it advertised itself on the network as well as allowing for 
> sufficient time to pass for the switches ARP data to age out.
>
> So why could you connect with some things and not others? Very possibly
>
> because of the path to the system. Some switches had correct entries
> and 
> others did not. Anything going through the old switch likely was
> getting 
> stuck while traffic that made it to the new switch was likely OK.
>
> But then I'm guessing a lot too. :-)
>
>  - Larry "DrFranken" Bolhuis
>
>
> On 4/14/2011 8:43 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.
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