accessing an HP printer on wan side of hardware firewall

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we're in a location with a single cable modem / router.  Then each tenant connects to that router with their own router / firewall to keep the other tenants out.

There's a shared printer (HP officejet Pro 8620) on the shared LAN (

We can print to it from our LAN ( but can't access it for scanning either from the computer's HP scan app nor from the control screen of the printer (it had been on the subnet originally so when you go into scan / to computer, we see our computer).

Is there a way to get to scan to / from the printer across the firewall?
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President and Janitor
I love your screen name, LOL.

So, your cable modem connects to the internet and is also a firewall and has an inside IP address of 10.1.10.x.

All of the tenant networks have routers with firewalls and they all have external IP addresses of 10.1.10.x and then whatever internal IP addresses they're using.

Your LAN is also connected like a tenant network and your firewall has an external IP of 10.1.10.x and an internal IP of 192.168.5.x.

Is this correct?

Now that I've typed all that, it might not matter.  I think what you'll have to do is simply open up ports on all those internal firewalls so the HP can communicate freely.

The HP printers use TCP 9100 for printing and TCP 9220 and 9500 for scanning.  I think they also use one of those for faxing.

You'll also need to open up SNMP - for whatever reason, all the way back to JetDirect days, if you don't have SNMP, you can't do squat with an HP printer.  That's going to be TCP 161.

It will also want to use NetBIOS - TCP 137, 138, 139 and 161 as well as UDP 137.

And, finally SLP on TCP 427 and UDP 427, in some cases.

There may be some other routing issues, based on how that network is set up.

Let me know your thoughts.
Thanks. I wound up connecting 1 computer on 1 subnet via USB and put the printer on the same subnet of the other printer.  Problem solved : )
Joseph HornseyPresident and Janitor

Cool.  Glad it's working!

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