SUMMARY: hostid Solaris 2.4 x86

From: David Visser (
Date: Thu May 11 1995 - 14:17:05 CDT

Original Problem:

        Has anyone seen a problem with the hostid being all zeros on a PC
        running Solaris 2.4 (x86)?


        Thanks to Nino of The Wellcome Trust Centre for Human Genetics,
        University of Oxford, for sending me the FAQ relating to this
        problem (attached).

        Unfortunately the fix is brutal! Re-install Solaris, yet again.
        I now have a new hostid, which makes one think if it really does
        relate to the physical ethernet address. Surely Solaris (x86)
        would support a configuration without an ethernet card...not
        desirable, but possible in a PC. What would be used for the
        hostid then??

Replies From:

        Douglas L.Acker <>
        Leonard E. Sitongia <>
        Stefan Jon Silverman <>
        Steve Raffensberger <>
        Nino Margetic <>

Thanks to all who responded.


How to maintain Hostid with reinstall.
OS RELEASE: x86 2.4
SYMPTOMS: Want to maintain the hostid across reinstalls.


The hostid in a Solaris X86 microcomputer needs to be maintained across
reinstalls. A unique hostid is generated and is stored on disk during
install. To maintain this across reinstalls this hostid is read before
the disk is destroyed and reused as the new hostid. So, if you use the
old disk and have not formatted it the hostid should be maintained
accross reinstalls.

There is a known problem in 2.4_x86 with Hostid preservation. If the
first installation on a machine fails or is aborted before the point at
which the non-zero hostid is created, or if a re-installation fails or
is aborted before the point at which the old hostid is restored,
subsequent re-installations generate an all-zero hostid.

A workaround for the above problem is as follows:

Begin a re-installation. When the installation reports that it is
creating the root file system, immediately reset the machine. The next
installation will create a non-zero hostid.

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