Author Topic: DHCP option in Hexadecimal on Juniper firewall  (Read 1842 times)

Offline Ronan

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DHCP option in Hexadecimal on Juniper firewall
« on: July 08, 2020, 05:00:45 AM »
Due to increased security following an attack, my client's subsidiary has a couple firewalls between their network with phones, and the IPBX. Furthermore they use their own DHCP server, and for some reason it's the one provided by a Juniper firewall, not a dedicated thing.

They try to use suboptions, so option 43 is sent to everything, with various suboptions, and if a cisco wifi AP gets the DHCP message, it reads its suboption, if a Mitel phone gets it, it should read option 125. That doesn't work, in fact the phone doesn't seem to read the suboption at all.

In hexadecimal the option starts with 7D (125) and the next characters are for the length of the option, the guy managing this doesn't know what to put there, we think it might be the problem. Any ideas ?

Regards


Offline ZuluAlpha

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Re: DHCP option in Hexadecimal on Juniper firewall
« Reply #1 on: July 08, 2020, 08:30:39 AM »
You can type and convert the DHCP options in to a hex converter. Microsoft's DHCP server does this as well.

Offline johnp

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Re: DHCP option in Hexadecimal on Juniper firewall
« Reply #2 on: July 08, 2020, 02:02:01 PM »
You can create the hex string for 125 using the dhcp config tool should start 00 00 04 03 from what I recall


 

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