FortiGate Next Generation Firewall utilizes purpose-built security processors and threat intelligence security services from FortiGuard labs to deliver top-rated protection and high performance, including encrypted traffic.
Article Id 190239


In some cases, it is possible to reach the FortiGate unit through a Ping, Telnet or SSH, but not through the web admin GUI.  

This article discusses some possible causes for a non-working GUI access.



  1. Interface settings.

    GUI access, HTTP and/or HTTPS, has to be enabled on the interface.

    CLI commands:

config system interface

edit <interface name>

set allowaccess ping http https


 Possible allow access settings: PING, HTTP, HTTPS, TELNET, SSH, FGFM (FGFM is required for FortiManager access), Fabric (Fabric needs to be enabled for Security Fabric access), SNMP (SNMP access).
  1. Trusted host configuration.

    If 'trusted hosts' are configured, the IP address of the computer used for the GUI access must be allowed as a trusted host.

    A whole subnet can be allowed as a trusted host.

    By default, trusted host settings are not configured, and administrative access is not restricted to any specific user IP addresses.

    Sample trusted host configuration:
config system admin         
edit "admin-test"
set trusthost1             
set trusthost2             
set vdom "root"
config dashboard-tabs             
 Changing the trusted host configuration:
config system admin     
    edit <admin user>
        set trusthost <1 to 10> <ip address>/<mask>         
        set ip6-trusthost <1 to 10> <ip6 address>/<mask>
 Trusted host settings are defined on an individual admin user basis, and are valid for all types of access.
 For example:
 If a user is trusted for access through SSH, it is also trusted for HTTP or HTTPS access.
  1. MTU along the path.

    After the first few synchronization and handshake packets, the web admin GUI HTTP and HTTPS packets can become larger than 1500 bytes.


    When a FortiGate network interface is connected to a network segment that supports such extended size packets.
    For Telnet or SSH, packets typically remain of smaller size.

    To be then able to use the web admin GUI, the fragmentation must be allowed at certain points in the network infrastructure (points, where a jumbo frame reaches a network segment that does not support it), or jumbo frames must be allowed along the whole communication path.

    Note about Jumbo frames: jumbo frames are packets that are larger than the standard 1500 maximum transmission unit (MTU) size. Jumbo frames increase data transfer speeds by carrying more data per frame, reducing the overhead from headers.

    All networks that carry jumbo frames must have network units that all support jumbo frames.
    Otherwise, jumbo frames will be dropped, when they reach network devices that do not support them.
  1. Admin access ports.

    By default, for admin login via GUI, the HTTPS port is configured to 443 and the HTTP port to 80.

    If those default settings are changed, access to the GUI will not be possible without specifying the custom-port used at the end of the URL.

    To verify which HTTPS/HTTP ports are configured for admin access:
show full | grep admin-port          
set admin-port 80 
show full | grep admin-sport
set admin-sport 443
In the event that the default ports have been changed, consider directly accessing the GUI using the specific port that is currently defined: http(s)://<address_of_appliance>:<custom port>.
For example: where 222 is the non-default port used to access GUI via HTTP.
If the ports needs to be changed to a new value or the default value, use the following syntax for HTTP access:
config system global     
set admin-port <integer> end
For HTTPS access, use the following syntax instead:
config system global     
set admin-sport <integer> end
  1. admin-server-cert (for versions 5.6 and above only).

    Enable the following debug and try to access the GUI again:
diagnose debug application httpsd -1
diagnose debug enable
Check if the output matches the following:
[httpsd 1746 - 1552998712    error] log_error_core[439] --
[Tue 19 12:31:52 2019] [crit] Can't open certificate file /tmp/admin_server.crt, nor /ssl/certs//tmp/admin_server.crt
[httpsd 1749 - 1552998714    error] log_error_core[439] --
[Tue 19 12:31:54 2019] [crit] Can't open certificate file /tmp/admin_server.crt, nor /ssl/certs//tmp/admin_server.crt
[httpsd 1752 - 1552998716    error] log_error_core[439] --
[Tue 19 12:31:56 2019] [crit] Can't open certificate file
/tmp/admin_server.crt, nor /ssl/certs//tmp/admin_server.crt
If it matches, proceed with the following:

config sys global

set admin-server-cert Fortinet_Factory


  1. Existing virtual IP is overriding admin HTTP or HTTPS ports.

    When a Virtual IP (VIP) has the same IP address of FortiGate interface and forwarding the same ports used for HTTP/HTTPS access (example 80 or 443), the VIP will override the administrative access.

    This should either be removed or changed such that it doesn’t overlap with FortiGate HTTP/HTTPS ports.

    This can be verified by checking the VIP list on FortiGate (Policy & Objects -> Virtual IPs) or running the debug flow.

  2. Check if any local in policy is configured to deny the access on the related interface.
conf firewall local-in-policy
sh full
    edit 1
        set uuid 794fef20-38ce-51ec-b995-89227f742faa
        set intf "wan1"
        set srcaddr "all"
        set srcaddr-negate disable
        set dstaddr-negate disable
        set action deny
        set service "HTTPS"
        set service-negate disable
        set schedule ''
        set status enable
        set comments ''
  1. Restart the HTTPS Daemon.

    none of the processes above fixed the issue, try restarting the HTTPS Daemon.
dia sys process pidof httpsd
Note the first listed process ID (this is the parent process).
dia sys kill 11 XX      <-- Add the process ID gathered in step 1.
Consider killing PIDs one by one. For example:


diag sys process pidof httpsd




di sys kill 11 1003

di sys kill 11 2956

di sys kill 11 3213

This restarts httpsd.


To restart the process, use fnsysctl killall httpsd.


In some cases, no HTTPS processes are seen to be running, so it may be necessary to restart the FortiGate firewall.

This may be the case if a recent firmware upgrade was completed and the GUI login issues are observed after the upgrade.

After the restart, the HTTPS process will appear in the results of diag sys top. It will be possible to log in normally through the GUI.


  1. If there are two default routes to with same distance and priority, e.g. 5, you may not be able to access GUI.
  •  Change distance for one route to 10 as an example.
  • Now you should be able to log in to the GUI and it should not freeze or hang.
  • Disable the setting: Retrieve the default Gateway from the server on the internal network interface.
  • If trying to access FortiGate using the WAN interface, make sure that the route is active or valid in the routing table.


Related articles:

Steps to enable remote management.

Configuring Administrator access to a FortiGate unit using Trusted Hosts.

Troubleshooting Tip : debug flow messages "iprope_in_check() check failed, drop" - "Denied by forwar....