DHCP options for PXE

Forum|Forum|16 years ago
December 28, 2009
7 replies
7713 views

I' m having problems getting the FortiOS DHCP server set to forward to my TFTP server. I' ve tried a lot of combinations and have gotten no where. Any help would be greatly appreciated. I would think all that' s needed is: option 1 66 31302e36302e3230312e32 (TFTP IP in hex) option 2 67 7078656c696e75782e30 (pxelinux.0 in hex) When I do a tcpdump the clients are still trying to hit the dhcp/gateway instead of the TFTP' s IP. I saw another place on the forum that recommended adding option 150 but I didn' t have any luck w/ that either. I know I' m doing something stupid. Can anyone shed some light on this? Thanks,

A

Anonymous_UserAuthor

Contributor

***bump*** Anybody?? Please! :)

rwpatterson

New Member

Please elaborate a bit. What are you trying to get done?

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Anonymous_UserAuthor

Contributor

No problem. We rely heavily on PXE booting in our environ. We are currently using the old 3com PXE server & TFTPD32 on our Win2k8 servers for PXE. Using any linux/unix DHCP server it' s really easy to define the boot flags to point the the TFTP server' s IP and boot filename -- thus eliminating the need to run a PXE deamon on port 4011. I can' t keep running this old 3com service as it corrupts the arp tables. Anyway, as a corporate mandate I have to use my Fortigate as our DHCP server. It works great however I can' t get the DHCP options to redirect to our TFTP server' s IP. My understanding is these are basically Linux boxes so I' m sure they are capable of doing basic things like this, but I can' t make it work for PXE. My firewall @ home has this setup to define the next-server & filename dhcp options: http://dl.dropbox.com/u/1445590/junk/pfsense.png I can' t seem to make this work using the FortiOS' s dhcp options. Are you able to see what I' m doing wrong? Thanks for taking a look at this for me.

FortiRack_Eric

New Member

I don' t understand how it worked on your linux box, but I' ve used this with some phones and thin clients to find the TFTP server: Option 1 66 AC16002D ( that is 172.22.0.45) Option 2 49 AC16002D (sun authentication server). Why the long string? Cheers, Eric

emnoc

New Member

What dhcp option does your pxe boot needs? tftp-server name ? or option 150? I bet it' s the latter.

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Anonymous_UserAuthor

Contributor

Eric, I was using the longer string because phone support made it sound like this would need the ' .' in the IP address. I' ve shortened it to 0A3CC902 which should be correct. So the strange thing is that using one or both option 66 or 150 my PCs still try to grab the boot file from the DHCP server (firewall). 10.60.201.1 -> Fortigate - gateway & DHCP 10.60.201.2 -> TFTP server It' s so easy to set this up using DHCPD & M$ DHCP; this is driving me crazy. Here' s what the PXELinux guys say you need: # PXE-specific configuration directives... option dhcp-class-identifier " PXEClient" ; option vendor-encapsulated-options 09:0f:80:00:0c:4e:65:74:77:6f:72:6b:20:62:6f:6f:74:0a:07:00:50:72:6f:6d:70:74:06:01:02:08:03:80:00:00:47:04:80:00:00:00:ff; next-server <TFTP server>; filename " /tftpboot/pxelinux.0" ; I' d love to try all four of these options, but the interface is limited to three. Is it possible to add a fourth via the command line? Thanks for the help so far. This has been much more helpful than the PAID support I received from Fortinet.

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Anonymous_UserAuthor

Contributor

Sorry I guess I have 2x accounts. guitarben = mrguitar