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Abel
Abel
New Member
September 15, 2023
Question

Computers or Devices behind FortiClient VPN not accessible from the LAN network

  • September 15, 2023
  • 4 replies
  • 4063 views

Dear Support,

I am newbie in Fortigate firewall and FortiClient VPN, I have been struggling with this issue for past 3 months, I hope you will help me resolve this issue. We are using Forticlient vpn to connect into the company LAN network to access resources and that is working fine but we cannot connect to any computer or device from the LAN network into our laptops, anything from the LAN behind the Forticlient is not accessible I cannot even PING the IP/hostname addresses on the Local laptops?

How can I establish a connection or communication from the LAN into our laptops or printers behind the FortiClient VPN? 

I am using FortiGate 40F V 7.2.5 build 1517 and FortiClient VPN 7.0.8.0427 on windows 10 and Windows server 2019 operating systems.

Thank you in advance.

Kind Regards,

Abel

  

4 replies

HarshChavda
Staff
HarshChavda
Staff
September 15, 2023

Hello @Abel ,

 

The FortiGate firewall might not have rules that allow incoming connections to the VPN clients. Check Network Address Translation (NAT) settings could be affecting the routing.  If you're using split tunneling, only traffic destined for the company's LAN will go through the VPN tunnel. The VPN policy might be set up in a way that only allows one-way traffic. 

 

Steps to troubleshoot:

Check Firewall Policies.

Check NAT Configuration.

If you're using split tunneling, try disabling it temporarily to see if that resolves the issue.

Check the routing tables to make sure that the LAN knows how to route traffic to the VPN network.

Make sure the Local LAN and Remote LAN are properly set, and the policy allows traffic in both directions.

 

 

 

 

 

hbac
Staff
hbac
Staff
September 15, 2023

Hi @Abel,

 

Please make sure you have a firewall policy to allow traffic from lan interface to ssl.root interface. That is the first thing you need to check. If it's already there, please run a debug flow as follows: (replace x.x.x.x with source and destination IP). 


di deb disable
di deb res
diagnose debug flow filter clear
di deb flow filter saddr x.x.x.x   <<<   Source IP 
di deb flow filter daddr x.x.x.x   <<<   Destination IP
diagnose debug flow show function-name enable
di deb flow show iprope en
diagnose debug console timestamp enable
diagnose debug flow trace start 500
diagnose debug enable

 

Regards,

dbhavsar
Staff
dbhavsar
Staff
September 15, 2023

Hello @Abel ,

Make sure in the route print that the route is being ejected if you are using Split Tunneling.
If not using it do a policy lookup to make sure that you have correct policy:
https://community.fortinet.com/t5/FortiGate/Technical-Tip-Firewall-policy-lookups/ta-p/192912

mle2802
Staff
mle2802
Staff
September 15, 2023

Hi @Abel,
Can you try to ping from LAN PC to FortiClient device and run the followig command on FortiGate:

di deb res
di deb flow filter addr x.x.x.x   (FortiClient assigned IP)
di deb flow filter proto 1
diagnose debug flow show function-name enable
di deb flow show iprope en
diagnose debug console timestamp enable
diagnose debug flow trace start 500
diagnose debug enable

Regards,
Minh

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