DNS not forwarding

Question

Hi all, 
 
 I am learning myself to work with a Sophos and have a UTM 220 @ home atm. I re-imaged it and configured it. 
 The wan and lan are working fine, when I hit the internet on the laptop i cannot find the dns. I manually have to add the DNS (8.8.8.8 and 8.8.4.4) in the ip4v configuration. 
 So I followed these settings Best practice , when i delete the DNS setting on the laptop I cannot reach the internet anymore. 
 Not sure what the next step is? 
 The modem/router settings are okay

With kind regards, 
 
 Denny

Louis-M · Accepted Answer

ok.... 
 firstly you would not be able to resolve anything on you client if there are no dns servers specified. You mentioned that you did this staticly ie you put an ip address, subnet and gateway into your client manually but did not enter any dns server details. In the above instance, you would probably find that you can ping 8.8.8.8 but not google.com as the client could not resolve. 
 When you activate DHCP on the UTM, you will find that it will give you those dns server details etc. You can verify this by doing an ipconfig /all on your client and you will see the dns servers listed that the UTM has supplied. I would leave it at that so that all your clients are dynamic and get the correct details and dns etc from the UTM 
 If you do set your client manually ie with a static ip/subnet & gateway, you will have to specify your dns servers eg for google's it's 8.8.8.8 & 8.8.4.4 
 However, you will have to ensure that there is a firewall rule on the UTM that allows local subnet > DNS > Internet (or 8.8.8.8 & 8.8.4.4 in the above example) 
 You can check if DNS is being blocked on the UTM by going to the firewall and clicking on "live log" and looking for a port udp/53 eg 8.8.8.8:53. if it's being blocked, it will show in red and will come under the default drop rule.