Ok Alan now you've got me ....
I do not have a /var/adm/hostid file nor do I even have a /var/adm dir.
Running a find on the system from the / dir all I get is:
[root@vern /]# find / -name hostid -print
/usr/bin/hostid
So now I'm really confused. Under Linux is this a responsibiity of libc or the
kernel?
Alan Cox wrote:
> > digging thru log files I found that flexlm was griping about a hostid
> > mismatch. So I ran the hostid command and I got: a8c02203
> >
> > What the ????? I have rebooted several times and I keep getting the
> > latter results (a8c02203). The only thing I added to the system between
> > the problem was VMWare. I have removed the vm kernel modules and I get
> > the same results (a8c02203).
> >
> > How does Linux determine its hostid? Does it use the MAC address?
>
> Firstly it uses /var/adm/hostid which holds 4 bytes of raw data matching
> the host ID in long format (ie low byte first).
>
> You can generate this with something like
>
> void main()
> {
> union
> {
> unsigned char h[4];
> unsigned long id;
> } hostid;
>
> hostid.h[0]=0xA8;
> hostid.h[1]=0xC0;
> hostid.h[2]=0X22;
> hostid.h[3]=0X03;
>
> write(1, &hostid, 4);
> }
>
> and dumping the result in /var/adm/hostid
>
> This might seem silly but since the PC has no hardware identitiy, ethernet
> cards can be reprogrammed trivially and the kernel can be trivially tweaked
> by a cracker to report a fake MAC address so it makes no odds.
>
> The PIII does have a real serial number, but people like that even less.
>
> Alan
>
>
>
> --
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--
Pete Graner
Senior Scientist
Information Technology Group (ITG)
Presearch Inc.
email work: [EMAIL PROTECTED]
email home: [EMAIL PROTECTED]
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