Change 'Faux NetBoot' name with NetBoot/SUS Appliance

[fritz_schlapbac]

Hi,

Does anybody know how to change the "Faux NetBoot" name of the NetBoot/SUS Appliance to something else?

Regards
Fritz

[DirkM2012]

I would like to know this too.

Thanks,
Dirk

[rockpapergoat · Accepted solution]

it's in the dhcpd.conf file as hex. look for this in the following file:

46:61:75:78:20:4e:65:74:62:6f:6f:74

https://raw.github.com/jamf/NetSUS/master/build/etc/dhcpd.conf

[fritz_schlapbac]

Thank you @rockpapergoat!

That worked.

[rshott]

I'm noticing when I change the NetBoot name that the Network Disk doesn't show up in the Startup Disk panel unless I keep the first word to 4 letters (EX: "Faux NetBoot" to "Test NetBoot" works but changing it to "Test1 NetBoot" doesn't). Does anyone know on why that would be?

TIA

[ski]

Just played with this and you have to keep the name the same length as 'Faux Netboot' (e.g. 13 characters. Technical you should be able to change the number of characters, but something on the server does not like that as when I did that we got strange behaviour such as multiple neboot servers showed up and then disappeared after a few minutes or no netboot servers showed up. FYI, check out this post for more information about how this option works:

http://serverfault.com/questions/318292/linux-dhcp-server-option-43-vendor-encapsulated-options-how-to-format-encode

cheers,

ski

[jguz]

For anyone still trying to do this, the name should actually be 12 characters long.

[daniel_behan]

Does anyone have an easier way to describe this fix or can anyone point me to a way of translating these hex names?

[daniel_behan]

Never mind, I got it.

[Josh_S]

I've done a bit of experimenting with this and found out how to make the NetBoot name anything you want, even if it has more/fewer than 12 characters.

Breaking down the encoded string, first byte being the "Option ID" and the second byte the "Option length", I noticed that the first few bytes of option "09" are identical, other than the length, to options "07" and "08". And the '0C' is hex for 12, the byte length of the encoded string.:

01:01:01:
04:02:FF:FF:
07:04:01:00:02:0E:
08:04:01:00:02:0E:
09:**11**:01:00:02:0E:**0C**:+46:61:75:78:20:4E:65:74:42:6F:6F:74+;

Replace '46:61:75:78:20:4E:65:74:42:6F:6F:74' with a hex encoded string of your choice, replace '0C' with the length of that string, and replace '11' with the length of that string plus 5 to cover the entire length of the option.

For example, my most recent NetBoot image is called "Casper 8.71 OS 10.8.4", the hex for this is "43:61:73:70:65:72:20:38:2E:37:31:20:4F:53:20:31:30:2E:38:2E:34" and is 21 characters long. 21 in hex is "15" and 21+5=26 in hex is "1A" putting that all together you get:

01:01:01:
04:02:FF:FF:
07:04:01:00:02:0E:
08:04:01:00:02:0E:
09:**1A**:01:00:02:0E:**15**:+43:61:73:70:65:72:20:38:2E:37:31:20:4F:53:20:31:30:2E:38:2E:34+;

Removing the line breaks:

01:01:01:04:02:FF:FF:07:04:01:00:02:0E:08:04:01:00:02:0E:09:**1A**:01:00:02:0E:**15**:+43:61:73:70:65:72:20:38:2E:37:31:20:4F:53:20:31:30:2E:38:2E:34+;

Substitute this string for the first "option vendor-encapsulated-options" in the dhcpd.conf file.

Edit: If you want your changes to remain, even if you change NetBoot settings, you'll have to edit the file located at /var/appliance/conf/dhcpd.conf

[joegyoung]

I am working on the same problem. sort of. This link is to the FOG Project. They have had some time to work on the same issue. This page explains the dchp.conf

http://brandon.penglase.net/index.php?title=Getting_*nix_to_Netboot_Macs

[fabian_ulmrich]

@Josh_S What do you mean with OptionID and Option length?

What I see is:
option vendor-encapsulated-options 01:01:01:04:02:FF:FF:07:04:01:00:02:0E:08:04:01:00:02:0E:09:11:01:00:02:0E:0C:46:61:75:78:20:4E:65:74:42:6F:6F:74;

That would mean, my option length is just 1 charakter right...? So default length is still :0C: means 12 characters.
Now my .nbi name has 20 characters....means I need to replace :0C: with :14: and :01: with :13: right?

Let's say my .nbi has 10 charakters, so 10 is :0a: ! But now...what is :0a: + 5 ? :D I don't get that running!

Also another question if you are experiences with NetSus...How can I use two different .nbi? Meaning, I can upload as much as I want, but it always will just shows 1 Option in my Boot Menu? Any suggestions?

Thanks so far!

Cheers,
Fab

[Josh_S]

@fabsen83

20 characters:
20 = 16 + 4 -> 14 in hex, replaces 0C
20 + 5 = 25 = 16 + 9 -> 19 in hex, replaces 11

10 characters:
10 -> 0A in hex, replaces 0C
10 + 5 = 15 -> 0F in hex, replaces 11

Replace the bolded parts above with the correct length indicators and replace the actual string with a hex encoded version and you should be set.

Using multiple NetBoot images, and having them advertised, is a much bigger question. It's possible, I haven't done it myself, but it involves a good understanding of the process and customizing the hex encoded strings with the correct options and values.

If you're still having trouble, if you can, post some example strings and I'll walk through how to encode them later today.

[cstout]

@Josh_S Thank you so much for your original post and recent further detail. I just came across this post and used your steps to successfully modify my NetBoot Appliance.

[fabian_ulmrich]

@Josh_S Thanks for your fast response. Now it worked for me too :) Pretty cool!
Think for multiple NetBook images I need to play around a little bit...for example I replaced 11 with 1a. Suddenly I had two NetBoot symbols showing up in boot menu. So it looks like it need to be combined in one hex code. I play around and maybe I can figure out something more. I'll let you guys know!

Thanks again Josh...really nice you figured that out.