DNS no longer works on Linux after migrating Firewalls

[pgeusen]

After replacing our Fortigates 100E with Fortigate 60F the DNS settings on our Ubuntu/Xubuntu workplaces no longers works. Windows PC's in the same VLAN have no issues with DNS.

When trying to ping form Ubuntu:

ping: adc001: Temporary failure in name resolution.

I have tried on multiple existing pc's but I have also installed new Ubuntu and then the same issue is there. 

What 

[ebilcari]

Based on your description it seems like a DNS suffix issue. Check if there is any configuration change on the new FGTs, you can find more information on this article.

[pgeusen]

When I try adc001.domain.local i get the sames response.

[pminarik]

Make packet captures of both and compare. DNS is ultimately quite simple, so you should be able to identify the difference.

[pgeusen]

When I send a ping from the Ubuntu PC I get no activity on the Fortigate. When I use the dig command I see activty but I see the following errors

• Flags: 0x8182 Standard query response, Server failure 
• Flags: 0x8183 Standard query response, No such name

[pminarik]

If the FortiGate doesn't even get the packet maybe it's going in a completely different direction?
Try checking the basics. (ARP, ping to gw IP, ping to some public IP, does the dst MAC of internet-bound packets match the FGT's MAC?, etc.)