Slow Browsing after enabling security features

Question

Hi! 
 We are testing a Sophos XG 230 Firewall. Internet access works but when we enable something like HTTPS Scan or Web policy or prevention internet speed extremly slows down. Especially HTTPS websites take 20-30 sec. to load. 
 I already checked various posts on that topic - they all point to DNS errors, so I checked DNS: 
 
 Static DNS is configured with 2 IPv4-DNS servers from our ISP. 
 Testing DNS name resolution is not working!

Could it be that something is wrong with our DNS configuration? How can we use all the security features without loss of performance?

Aditya Patel · Answer

Hello Cristian , 
 Could you follow the steps ,it does seem the delay is not caused on the firewall. 
 1. Enable Debug for Service Awarrenhttp Go to Shell Option 5>3 service awarrenhttp:debug -ds nosync 
 2. Run the command to capture the logs .# tail -f /log/awarrenhttp_access.log | grep 103.23.140.55 
 3. Open browser and open "http://103.23.140.55" 
 4. Share the transition logs and run the command in 1 again to disable debug.

HuberChristian · Answer

This is quite informative. See first Package: 
 authtime=0 dnstime=6030752 cattime=0 avscantime=0 fullreqtime=6094419 
 This means, nearly all the time of your fullrequest is needed by DNS Categorization. You are probably using a slow DNS Server. 
 
 In your second request, there is no more DNS Resolution needed, (Because it probably allready has the IP of your Name in Cache). But here, Categorization time again is using nearly all of your Requesttime: 
 authtime=0 dnstime=0 cattime=6059672 avscantime=1752 fullreqtime=6365649 
 Depending on the Version, Categorization is done by DNS as well if I remember correctly. 
 
 Maybe you can switch to another DNS Server, preferably the one of your ISP?