Internal Host Detection Issue

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Internal Host Detection Issue

L1 Bithead

Hi there,

 

I have a question on the correct use of internal host detection and internal/external gateway config. The behaviour I want to achieve is when a client is internal to the LAN GlobalProtect will detect this and not bring up the tunnel and pass all network traffic transparently out the LAN connection, as if it wasn’t there. When external, the client tries to establish the tunnel. I have no requirement to tunnel internal traffic, it needs to traverse the LAN as if GlobalProtect wasn’t there.

 

I have an external gateway & portal configured, there is no internal gateway. A “no NAT” rule and policy are set up so the client machines can communicate with the external gateway, even if they are internal. I understand this is best practise so clients will get config changes from the firewall regardless of where they are connecting from. The NAT & policy that allow this are working as I can communication in the logs from internal clients. No direct access to the local network is enabled and app is in “always on” mode as I want all traffic to be forced down the tunnel if the client is external to the LAN.

 

When clients are external to the network, everything works fine and as designed.

 

However with internal clients, there can be a delay in connecting, sometimes 30 seconds or longer before it realises it is on the internal LAN, and GlobalProtect backs off. Sometimes the yellow “connecting” message appears, asking you to be patient. Some clients are fine, and immediately detect the internal LAN and back off.

 

A small number of clients will not detect they are on the internal LAN at all. After the user authenticates, the GlobalProtect client tries to do something, then falls back to disconnected state. Firewall logs show the authentication and client configuration was successful, so something strange is happening on the client side. In this situation the app appears to be allowing some outbound network traffic from the device to the local LAN, but no inbound, resulting in an internal client that is orphaned from the network.

 

Clearly something isn’t quite right, how can I achieve the behaviour I want?

 

On internal host detection the documentation says “The GlobalProtect app connects to the internal gateway after performing internal host detection to determine the location of the endpoint.”

 

What is the client behaviour once it detects it is internal to the network? I don’t have an internal gateway configured, could this be the problem? Is the client looking for an internal gateway?

 

Many thanks,

3 REPLIES 3

Cyber Elite
Cyber Elite

Hi @PKCCommsTeam 

For this you do not need an internal gateway. You wrote that you have configured always-on mode: pre-logon or user-logon? What globalprotect version do you use?

Hi there,

I managed to work this out but forgot to reply.

I had to set up an internal gateway operating in "no tunnel" mode to allow the client to pass traffic as normal when on the internal LAN.

 

I previously did not have an internal gateway set up, things are now working as desired.

Thanks,

@PKCCommsTeam

 

Can you share the setup you have for the internal gateway. I have a similar setup and similar issue. Are you using DHCP option on the internal gateway as well.

 

Thanks,

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