Removing DNS Forwarders for Securly Filtering

Step-by-Step Instructions

Step 1: Identify Your DNS Configuration

Examine your DNS server settings to locate the Securly DNS forwarder IP addresses currently in use.

Step 2: Remove Securly DNS Forwarders

Access your DNS server (e.g., Windows Server DNS, Linux BIND, router/firewall DNS settings) and remove the Securly DNS forwarder IP addresses. The specific IPs to remove depend on your assigned cluster:

Cluster	DNS IP Addresses
US West	50.18.216.174, 50.18.216.175
US East	184.72.238.58, 184.72.238.71
US East 2	18.220.192.95, 18.220.192.111
Canada	35.182.41.111, 52.60.36.138
UK	3.10.96.65, 3.10.73.55

Step 3: Configure Alternative DNS Forwarders

After removing Securly’s DNS IPs, configure your DNS servers to use alternative DNS services, such as:

• Google Public DNS: 8.8.8.8 and 8.8.4.4
• Cloudflare DNS: 1.1.1.1 and 1.0.0.1
• Your Internet Service Provider’s (ISP) DNS servers

Step 4: Disable IPv6 (If Previously Disabled)

If you had disabled IPv6 to accommodate Securly’s requirements, consider re-enabling it if your network infrastructure supports it. Conversely, if you wish to keep IPv6 disabled, ensure that your new DNS configuration is compatible with IPv4-only settings.

Step 5: Clear DNS Cache

To ensure that changes take effect promptly, clear the DNS cache on your DNS servers and client devices:

• Windows Server: `ipconfig /flushdns`
• Linux (BIND): `rndc flush`
• macOS: `sudo dscacheutil -flushcache; sudo killall -HUP mDNSResponder`

Step 6: Verify DNS Resolution

Confirm that DNS queries are resolving correctly through your new DNS forwarders:

• Windows: `nslookup example.com`
• Linux/macOS: `dig example.com`

Ensure that the responses come from your newly configured DNS servers.

Additional Considerations

• Firewall Rules: Review and update any firewall rules that were configured to allow traffic to Securly’s DNS servers. Ensure that these rules are modified to permit traffic to your new DNS forwarders.
• SSL Certificates: If you installed Securly’s SSL certificates for HTTPS filtering, consider removing them from client devices to prevent potential trust issues.
• Group Policy Objects (GPOs): If DNS settings were deployed via GPOs in a Windows environment, update these policies to reflect the new DNS configuration.

Support

If you encounter issues during this process or require further assistance, please contact your DNS service provider or network administrator.