Troubleshooting Tip: Unable to connect to FortiGuard servers

[patelr]

Description	This article explains possible reasons why FortiGate is unable to connect FortiGuard servers and offers steps to troubleshoot the problem. The 'Unable to connect to FortiGuard servers' error message can be seen in two places: Dashboard -> Status -> Licenses. System -> FortiGuard -> FortiGuard Updates.
Scope	FortiGate, FortiWeb.
Solution	The communication between FortiGate and FortiGuard for web filtering and antispam is different from the communication for antivirus and IPS. Check connectivity to FortiGuard servers by checking to ensure FortiGate correctly resolves DNS with the following hostnames: exec ping service.fortiguard.net exec ping update.fortiguard.net exec ping guard.fortinet.net If the DNS resolves, move to Step 2:      2. Run 'diagnose debug rating' in the CLI: diagnose debug rating The output of the command 'di de rating' displays flags next to servers: I: The server initially connected to validate the license and fetch the server list. Typically, only one server will have this flag. The IP address FortiGate received when resolving the name service.fortiguard.net. If the administrator has not overwritten the FortiGuard FQDN or IP address in the FortiGuard configuration, there are usually two or three servers with this flag. S: The IP address FortiGate received from FortiManager. T: The server is not replying to FortiGate queries. F: The server is down. If all servers in the list have F(ailed), this may mean either all FortiGuard servers on the Fortinet side are down (unlikely), or that this FortiGate has a problem reaching them at the network level.      3. If there are VDOMs enabled, all communication to the FortiGuard network is initiated from the management/root VDOM only. config sys global     set management-vdom "root" end However, from firmware version 7.2 onwards in multi-VDOM mode, users can choose from which VDOM FortiGuard services and updates are initiated, instead of being locked to the management VDOM. config global     config system fortiguard         set vdom "root"     end end The VDOM specified should be able to reach the internet and should be able to resolve DNS queries. To set up FortiGuard services on a non-management VDOM: Specify the VDOM to be used under 'config system fortiguard'. Ensure that the specific VDOM has connectivity to the internet. FortiGate should be able to resolve the DNS from within the VDOM, so that the FortiGuard services may resolve the server name using the specific VDOM.      4. Verify AV & IPS Definition and Filtering Services: Check AV & IPS Definition under System -> FortiGuard -> AntiVirus & IPS Updates -> Update AV and IPS Definitions. Check Filtering Services under System -> FortiGuard -> Filtering. Anycast servers: It is recommended to disable anycast and switch back to unicast servers. config system fortiguard set fortiguard-anycast disable set protocol udp set port 8888 set sdns-server-ip 208.91.112.220    <- end For Fortiguard's SDNS rating service, there are two modes in FortiOS: mode 1: Use of unicast network, which uses DNS over UDP protocol for FortiGate and FortiGuard transactions. mode 2: Use of anycast network (default), which uses DNS over TLS protocol for FortiGate and FortiGuard transactions. To use UDP/53: config system fortiguard     set fortiguard-anycast disable     set sdns-server-ip "208.91.112.220" end To use DoT (TCP/853). config system fortiguard     set fortiguard-anycast enable end With Anycast, FortiGate is only aware of one single server IP. This is a floating IP address that will connect to the closest server geographically, and if this server is down, it will point to another server instead. With Unicast, the FortiGate must maintain a list of servers that it tries and if one stops working it then switches over to another. In many cases, problems related to FortiGuard are caused by ISPs. Some ISPs block traffic on port 53 that is not DNS or that contains large packets. In those cases, the solution is to use port 8888. Other ISPs block traffic to HTTPS port 8888. In those cases, the solution is to use UDP port 53.  Related port information: Encrypted Virus Samples auto-submitted to FortiGuard – 25. DNS lookups – 53 UDP. FortiGuard Server List requests to FortiGuard – 53 UDP. AntiSpam or Web Filtering rating lookup queries to FortiGuard – 53 UDP or 8888 UDP. URL/AS rating lookup queries to FortiGuard – 53 UDP. Real-time Black List (RBL) lookup requests to RBL services – 53 UDP. Fortinet Device Registration to FortiGuard – 80 HTTP. Firmware and Signature Downloads from FortiGuard – 443 HTTPS. FortiGuard Server List requests to FortiGuard – 1027 UDP / 1031 UDP. AntiSpam and Web Filtering rating lookup requests – 1027 UDP / 1031 UDP. AV/IPS Push / FortiGuard to FortiGate – 9443 UDP.      5. To configure FortiGate to use worldwide servers or only servers located in the USA, run the following command in the CLI: conf sys fortiguard set update-server-location [usa/any] end This can also be done under System -> FortiGuard -> FortiGuard Update in the GUI. Some debug commands for FortiGuard: di de reset diagnose debug application update -1 diagnose debug enable The following command can also fix various issues with FortiGuard servers. In this example, 212.48.23.12 is used as the IP for the interface to the ISP router. config system fortiguard     set fortiguard-anycast disable     set protocol udp     set port 8888     set sdns-server-ip 208.91.112.220     set ddns-server-ip 173.243.138.225     set source-ip 212.48.23.12 end config system dns     set primary 8.8.8.8     set source-ip 212.48.23.12 end   Notes: Suppose connectivity to FortiGuard is required through one of the outgoing interfaces. In that case, it is possible to use 'interface-select-method' with the 'specify' action and then select the outgoing interface under the FortiGuard configuration. See Technical Tip: Functionality of 'set interface-select-method' for local-traffic with SD-WAN for more information. config system fortiguard     set interface-select-method {auto|sdwan|specify}     set interface WAN Interface Starting from 7.2, initiating FortiGuard services and updates is not locked to the management VDOM. See Allow FortiGuard services and updates to initiate from a traffic VDOM for more information. If the issue persists, contact Fortinet support. License errors may be found in two places as shown below: Dashboard -> Status -> Licenses. System -> Config -> FortiGuard. If DNS issues occur, the following output will be seen in the CLI: Verify DNS settings in FortiWeb under Network -> DNS. Verify the reachability of the DNS IP. If the DNS is private, change to a public DNS and verify the connectivity. If the DNS resolves, check reachability. If there is any firewall, allow the ICMP for FortiWeb. If there is any firewall in place, allow traffic to all destinations for testing purposes. If this fixes the license issue, it indicates the issue is on the firewall policy level. If all checks have been performed successfully, collect the following logs and share them in a ticket created with support: di de application fds 7 di de application updated 7 di de enable execute update-now To disable the debug: di de di FortiGuard licenses and the communication to FortiGuard are viewable via GUI through System -> FortiGuard as well as through the CLI using the following commands: di autoupdate versions The output is quite long, but it is possible to pipe the output to grep: di autoupdate versions | grep -A6 "IPS Attack Engine"