FortiGate GUI not responding

[zoriax]

Hi everyone ! 

I'm facing a very strange issue. I'm running FortiOS 7.0.8. On some of my FortiGate, I can't access to web gui trough LAN interface. On my browser, I can see the certificate warning and after I accept it, the donut is running indefinitely.

If a do a packet capture during this, I can see paquet transiting trough my FortiGate to web interface port. 

If i go trough wan interface, I can access to the login page without any problem and suddenly, I can access to web gui trough lan for a while...

Very very strange no ? Someone can help me to understand what appends ? 

Thanks

[abarushka]

Hello,

As far as I understand when the issue is triggered FortiGate receives packets on LAN port. I would recommend to check whether FortiGate also replies back to the client.

[zoriax]

Hello,

I think it's not a firewall problem but a process problem. As I said, when I reach web gui from WAN IP (WAN interface) it works and the immediately LAN access web gui works for a wile.

[abarushka]

Hello,

Traffic sniffer will help to find whether firewall is replying. Also traffic sniffer will help to identify whether TCP/TLS sessions were established successfully. Moreover, you may consider to use Firefox built-in Network Monitor tool in order to check the communication.

[zoriax]

As I can see from my browser, I have some 401 http when trying to reach web gui page. 

I have nothing in trusted host or other settings... What's that ?