66 option (next-server) is not work, PXE clients wants using siaddr

RouterOS General
1

Hello, my pxe-boot clients always wants to boot from dhcp siaddr address.
Options are sets correctly, and 67 option (bootfile name) works properly, but 66 option just ignored.

For example:
It is working if I set next-server option for all network:

    /ip dhcp-server network
    add address=192.168.0.0/22 dns-server=192.168.1.10 gateway=192.168.1.1 netmask=22 next-server=192.168.1.51'

But I needed to set next-sever per client, not for all network, so I removed next-server for network, and add this as option:

    /ip dhcp-server option
    add code=67 name=boot-file value="s'/pxelinux.0'"
    add code=66 name=next-server value="s'192.168.1.51'"

After it I attached this options to wanted lease and its not work. Its not work too if I attach this option to network whole.

According my DHCP-Server log, options are sends correctly, and 67 option (bootfile name) works properly, but 66 option just ignored by clients.
In first case ( next-server per all network ) it changes siaddr option too, and it works fine.
But in second case ( next-server as 66 option ) siaddr remains the same and equals dhcp server address, it is not work. Clients wants to boot from siaddr, not from 66 option.

So I have next question is the any way to set siaddr option per client not for all network?

2

You need to add the DHCP option to your DHCP binding. Took me a day to figure this out when trying to set an NTP option.

 /ip dhcp-server network add address=192.168.0.0/22 dns-server=192.168.1.10 gateway=192.168.1.1 netmask=22 next-server=192.168.1.51' dhcp-option="boot-file"

Don’t know the command line syntax to add the second option without playing around, can do it via winbox easily.

3

Hello andsmith,
Yes I know, but I’ll need to add different options to different clients later, and it’s not working with next-server option (66), but working with boot-file option (67)

For me I found the workaround:
As my clients uses IPXE bootloader, so they support to set boot-file option (67) like this:

tftp://192.168.1.51/pxelinux.0

But I think it may not work with simple bootloaders.
It would be nice if MikroTik added the setting next-server (as siaddr) function for a separate dhcp-lease

4

I know this is an old issue, but I wanted to chime in and say that this would be really good to have.

I’ve been using options and option sets with great effect to customize network boot procedures for all the different machines on the network (IA32, IA64, ARMv7, etc.)

However, the IA32 BIOS is very fussy, and only honours the next-server field. Unfortunately this is not something that can be affected using option sets - being able to specify the next-server on a per-lease basis (the same way you can do with DHCP options by using option-sets) would be a great feature addition.