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Hostid in a Linux machine

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Advanced Member level 4
Dec 11, 2002
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linux hostid

At a termal iwth R7.2. I type host id and i got a number. Anyone know wherethis number come from?

hostid linux

You can find hostid command in sh-util-2.0-i386-1 package.
Download sh-util-2.0 source and will
find hostid.c in src directory.
You'll see that host id you can get with function:
long gethostid();
see also:
int sethostid(long hostid);

man gethostid
man sethostid
and read man pages :))))

flexlm linux hostid

No, you misunderstood me. The question I ask is where this hostid come from. In a workstation, the hostid is programmed by the manufacturer in a eeprom(or flassh) BIOS. Some EDA application get the ID from a dongle. NIC address and hard drive signature can be a source of hostid. What I ask here is how the Linux OS calculate to give us a hostid number.

flexlm how is hostid calculated?

ok... :))
may be this call is described in libc or glibc or others... I don't know, but can see, if you want. There you can find right way how to calculate default value for hostid. Next lines are taken from man page of gethostid:

"This normally resembles the Internet address for the local machine, as returned by gethostbyname(3), and thus
usually never needs to be set."

May be gethostid() or sethostid()
is a syscall to kernel, I don't
know, at this moment, but I told
you, that If you want, I can see

to set new hostid, you must have superuser privilegies...

how to change hostid

I think that default value is based on Ethernet address or HDD serial or model, firmware version and etc...

you can see also
hdparm command

and this ioctl


where fd is file descriptor for
/dev/hda for example with open()
and id is struct hd_driveid.


linux machine id

btw I'm with Slackware 8.1

how to find the host id in windows machine

wzdreamer said:
ok... :))

to set new hostid, you must have superuser privilegies...

If you can set the host id, how can the EDA protect they software. They are not stupid ! Remember the software in linux is protect by Globelstrotter Flexlm. The host id have to be a fix string, it's can't be modified easily

host id/machine id or dongle number

I can't understand why you can't change your MAC? or DISK Id, which is your volume serial, if you use Windows...
You can change host id easy, if the system is yours... but you can't make valid license easy!!!!

If you have a valid license you can adjust your PC to work with it... But how to make valid license?????

I did it for some tools... i.e. Xilinx foundation ISE 4.2i....

I copied and install the CDs... take valid license from my friends, who bought it and changed my MAC address... with simple i2c modifications....

sh-util-2.0-i386-1 gethostid

You are right that Flex LM is serious copyright protection.... but not perfect...

there aren't perfect copyright protection....

I have my own license manager similar to FLEX lm in ideology.... but differs in some cases... I don't believe that it's better than FLEXlm... but it's mine :))))

how to find host id of linux server

now i wrote a simple source for you
it works....


#include <stdio.h>
#include <unistd.h>

int main() {
long id,res;

// get real (default) hostid
id = gethostid();
printf("current hostid is: %x\n",id);
// set new hostid if is superuser
res = sethostid(0x11223344);
if (res == 0) printf("if result is zero - success! (%d) \n",res);
// check if it is changed....
id = gethostid();
printf("current hostid is: %x ;-PPPppppp\n",id);

how to find host id of system, linux

compile with

gcc -o changehostid changehostid.c

where changehostid.c is the source, which I pasted...
and changehostid is the binary...

run it with

and you'll see the result...


don't forget that you must be a superuser.... i.e. root


fix hostid linux

That's good. I tested. it works

changing the host id in windows

I know, that works :)))

Never!!! Never forget this:
"Root CAN DO EVERYTHING on its own system!"


but don't forget the label on the top of the forum
"Software piracy is wrong!"

btw I'm software and hardware developer :)))

be well,
Wazard Dreamer

set host id i386

Hey smart Wazard Dreamer,
Can you show me how to do it easily with Sun machine .

change hdd model

I haven't sun... sorry...

If you want - give me root access to your Sun workstation :)))

hostid of a linux machine

Hi wzdreamer,

Does the proposed way change Linux host ID permanently? Or I shall ask this question by below separate ones :

1. Will the new host ID be valid in current shell only?

2. Or will the new host ID be valid in all shells open afterwards?

3. Or will the new host ID be valid even after next power-on?

If the new host ID be valid in current shell only, and not spreading over other shells, this might mean multiple host IDs at the same time at one machine, and mean multiple.....

cant set specific hostid

no multiple hostids... you know.....

after power-off and power-on will be restored default value.... value, which you will see in first running of the program, which i paste...

If your problem is to change it permamently, after power down, the right way is different :)))

but have you needs to change it permanently, when you can change it every time, when you needs using this tool.
You can add it in /etc/rc.d/rc.local
and it will be executed each time when you reboot your system...

steve88 did you try it?

slackware thunderlan

permanently changes ;PPpppp

may be the question of edaguy69 is:
"Where is hidden hostid?"

I don't know at this moment... but can see
if you are looking for...


hostid adresse mac linux

"permanentlly" changed hostid is stored it /etc/hostid...
So you haven't needs to change it every time, when you reboot
your system... next time, when you type hostid, it will be
read from /etc/hostid
To restore original hostid, just remove /etc/hostid

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