Fortigate Troubleshooting

There are most common issues which can happen (users report):

Most important is to realize what can it cause and what resource userst are trying to reach.

can't reach internet

possible issues:

at client computer where is internet inaccessible I need to make sure about next questions:

is computer in my network? (mostly: network address, gateway, DNS servers) : India
```
ipconfig /all
```
- FALSE: Is main router accessible? Is DHCP running? Have DHCP free IP addresses?
is my gateway responsible?
```
ping <gtw-ip-address>
```
- FALSE: Is router stucked? Is some Switch on the way broken?
is my internet line responsible?
```
ping <my-public-ip>
```
- FALSE: Isn't change in some firewall rule?
is some IP address in internet responsible?
```
ping 1.1.1.1
```
is my DNS responsible?
```
ping <my-dns-ip-address>
```

When is false only last question, you need to troubleshoot DNS servers. That is external service and is substituble.

For work our systems there is need our internal DNS - usually on IP address finish with 5 - 10.0.???.5

Check your DNS server:

ping <my-dns-ip-address>

When is unresponsible, you can use (for work internet addresses at least) public DNS servers like:

or some from your internet provider

There is important realize location of this server - local vs remote (USA)

possible issues - local server:

It isn't fortigate issue

possible issues - remote server: