GlobalProtect prelogon and internal gateway detection

BenKnorr2 — Thu, 06 Mar 2025 18:47:20 GMT

I've been doing mixes of internal and external gateways with customer forever (I usually forget that "always-on" must be enabled for internal gateway detection to even be allowed in the first place).

I'm working on a pre-logon implementation that also would benefit from leveraging internal gateways/no-tunnel while inside the enterprise network. I'm seeing some wild behavior at the moment...

THIS TEST IS OCCURRING WITH CLIENT CONNECTED TO CELLULAR HOTSPOT WITH IP ADDRESS ON PUBLIC INTERNET, OUTSIDE MY NGFW

Device, while on internet/outside UNTRUST zone on my NGFW, is configured to connect to my portal as "prelogon" : me.example.com.
Device successfully connects to prelogon portal, then EXTERNAL GP gateway, and is shown in NGFW GP-Gateway remote-users pane as "pre-logon" user as expected. On the device at logon screen, however, it shows "Internal Gateway (Connected)". ... [this is curious since the device is outside my WAN boundary]
NGFW globalprotect external gateway status
internal gateway, while pre-logon is outside WAN
I am able to login successfully on client, and GP client immediately shows that it is connected to internal gateway. On NGFW, it still shows "pre-logon" user on the external gateway.
gateway status
On client, doing test to www.ifconfig.co , it shows WAN address of my GP external gateway, as if it were connected to the external gateway. The GP settings show no IP information, consistent with it thinking it is connected to internal GW. ipconfig /all shows NO tunnel interfaces, no tunnel information, no IP address other than the wifi address and gateway of my LTE hotspot I am connected to.

ROUTE INFO ON CLIENT DURING THIS EVENT:

C:\Users\me>route print
===========================================================================
Interface List
3...94 65 9c 1b be 1d ......Microsoft Wi-Fi Direct Virtual Adapter
15...94 65 9c 1b be 1c ......Intel(R) Dual Band Wireless-AC 7265
1...........................Software Loopback Interface 1
===========================================================================

IPv4 Route Table
===========================================================================
Active Routes:
Network Destination Netmask Gateway Interface Metric
0.0.0.0 0.0.0.0 192.168.83.144 192.168.83.138 35
127.0.0.0 255.0.0.0 On-link 127.0.0.1 331
127.0.0.1 255.255.255.255 On-link 127.0.0.1 331
127.255.255.255 255.255.255.255 On-link 127.0.0.1 331
192.168.83.0 255.255.255.0 On-link 192.168.83.138 291
192.168.83.138 255.255.255.255 On-link 192.168.83.138 291
192.168.83.255 255.255.255.255 On-link 192.168.83.138 291
224.0.0.0 240.0.0.0 On-link 127.0.0.1 331
224.0.0.0 240.0.0.0 On-link 192.168.83.138 291
255.255.255.255 255.255.255.255 On-link 127.0.0.1 331
255.255.255.255 255.255.255.255 On-link 192.168.83.138 291
===========================================================================
Persistent Routes:
None

IPv6 Route Table
===========================================================================
Active Routes:
If Metric Network Destination Gateway
1 331 ::1/128 On-link
15 291 fe80::/64 On-link
15 291 fe80::a107:9e6c:1abc:8153/128
On-link
1 331 ff00::/8 On-link
15 291 ff00::/8 On-link
===========================================================================
Persistent Routes:
None

192.168.83.0 is the internal network on my cellular hotspot and exists entirely outside of NGFW. NGFW knows nothing about this network from security, routing, NAT etc.

NGFW logs show no traffic from source IP of this client. The only indications of connectivity on this client from the NGFW side is that I see a "pre-logon" user connected on this device through the external GP gateway. No traffic logs are generated from anything this client does. From the client side, I am able to access all "internal" resources as if I were connected via external GP gateway. ifconfig.co web page shows IP egress address as if I were connected to external GP gateway.

My concern and misunderstanding is with how internal gateway detection works. It seems like at the pre-logon stage, the client successfully reaches the portal, gets a portal config which includes an internal gateway detection element and internal gateway defined. It seems like it is reaching out to an internal DNS server at the pre-logon stage (which I need it to be able to do in order to talk to Active Directory for user authentication at login prompt), and it thinks it is actually inside. The user supplies credentials at login window and GlobalProtect shows "internal" after they login.

Is there some other way to handle this "internal detection" phase with pre-logon in the mix such that "pre-logon" is able to access AD for auth, but not allow the PTR lookup to succeed? Short of some DNS trickery where I create a zone that cannot be resolved in my pre-logon CIDR, I can't imagine how else to make this work. I've seen nothing in PAN documentation that suggests anything other than including an internal gateway is possible.

Re: GlobalProtect prelogon and internal gateway detection

BenKnorr2 — Thu, 06 Mar 2025 20:09:25 GMT

oof. so my "test" hotspot had wifi turned on while in hotspot mode. chaos ensued. In my defense, in previous hotspot, it did not allow wifi to be enabled prior to enabling the hotspot while this one lets it happen.

With proper hotspot, the internal detection has happened more reliably now. My question still stands regarding "if prelogon's connection to its respective gateway happens, which by definition implies internal access to AD/DNS, what does the user-side do regarding the internal/external detection if it is defined in a portal agent config?"

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GlobalProtect prelogon and internal gateway detection

Re: GlobalProtect prelogon and internal gateway detection