SUMMARY Machine unvisible from network after reboot

From: Andreas Priebe (
Date: Sat Dec 19 1998 - 02:42:39 CST

Hi all,

sorry for the late summary - but the problem remains unresolved :-(

Here the original question:

> we have the following problem with our new E450 (solaris 2.6 5/98).
> After reboot the machine is not visible from the network - only after a
> network action initiated from the machine itself (ping, telnet etc.)
> it is reachable via IP from other machines.
> The same seems to happen after some days of not using the machine
> actively on the network.
> This is very annoyning since we support the machine remotely!
> I vaguely recall seeing this on a E4000 with Solaris 2.5.1, but this
> machine is in havy production/network use now, so I cannot verify
> this at the moment.
> Any ideas?

Yesterday we had to change the machine back to 2.5.1 (due to reasons with
a special software we use) - and to make a long story short: its all the
same as with 2.6.

I thing the explanation by Kevin Maher (
comes nearest:

> Sounds like this machine is connected to an ethernet switch. If so, the
> switch might not yet have a MAC entry in its table for the system. By
> initiating a connection from the host, the switch would then cache the
> MAC address for future use, but they will expire after a period of
> inactivity. One way around that would be to hard-code the switch with
> the address. Another way I've had to resort to in the past is to write a
> simple cron script that will initiate a ping at fixed intervals. This
> keeps the MAC tables active for those touchy devices that disappear.

Indeed the Machine is connected to a larger Switch/Router (Xylan Omniswitch)
which I have no control over but which gives problemes in other relations
We stayed with the "solution" of a crontab-ping every 15 Minutes to a nerby

Here are other answers/suggestions I received:

> John White
> Have you checked how the machine is sensed on the network routing level?
> That is, after reboot, when the machine isn't "viewable", how does it
> look to the switch/hub it's plugged into?

Sorry, but we have no control over the network equipment so I couldn't check.

> Marais Gert
> The problem is in your arp-table. The moment you ping another machine
> the ether address advertise on the net and everybody can see it.

> Sean Quaint
> Had the same thing happen in a very small network of Sparc 5's. My fix was to
> power down the three hubs, wait a few moments, then power them up again. Not
> sure why, but it worked. Maybe some bad packets roaming around.

This is a production environment, it is very difficult to
power down the Switch/Router other than in emergency cases.
But some of our other network problems indeed vanished for a while,
when we once had to power down the Xylan beastie.

> Paul V. Alukal
> Is the netmask correct on the ip address? (see /etc/netmasks file).

Yes, everything OK.

> this may be a long shot, but could your problem be a DHCP lease expirition
> issue??

No DHCP is used at this site.

Thanks to all who answered.


* Andreas Priebe                E-Mail: *
* Promos consult GmbH & Co KG   Tel/FAX:             030 243 227 -13 / -29 *

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