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Posted: 2021-07-0103:53 AM
DHCP Option 43 Messes with Hewlett Packard JetDirect Configuration
This was originally posted on APC forums on 6/19/2013
I'm creating this post for the benefit of anyone else who might experience this same (yet extremely obscure) case, and stumble across it with a web search.
I had to configure an AP9617 recently, and so in order to avoid breaking out the old laptop that I keep around only because it has a serial port, I added the APC Vendor-Specific Cookie (Option 43) to my network's DHCP server. Figuring leaving the option in place wouldn't cause issues with other DHCP leases, I left Option 43 configured on the DHCP server, thinking that if I ever had to install subsequent 1st Gen NMCs, they'd "just work" without any additional tinkering.
However, I noticed today that one of the HP LaserJets on the network was reporting as Offline. A printout of the printer's configuration page revealed that the printer was receiving its reserved IP address as normal (192.168.1.216) and proper default gateway was set (192.168.1.1), but that the Subnet Mask was being set as 126.96.36.199 (see attached scan of config page) instead of the standard 255.255.255.0.
Rebooting the printer (which renews its DHCP lease) resulted in no change.
Removing the APC Vendor-Specific Cookie option from the DHCP server, and then rebooting the printer resolved the issue.
So after you've set Option 43 to gain access to an old-school APC NMC (and probably removed the vendor specific cookie requirement in its network settings), don't forget to remove the option from your DHCP server!