Windows 7 When is defined second DNS server used ? What about router IP as DNS?

[pstein]

I am working with a couple of inhouse computers (Desktop & notebooks) in a LAN behind a router.

In the past I have always setup the router IP 192.168.0.1 as DNS server in the Win 7 LAN settings dialog.
Does that make sense?

Because the router hardware itself does not contain a DNS server (or at least with some very poor caching) he has most of the time forward all DNS request from e.g. my notebook to the outside broadband providers DNS server.

So why not entering directly the broadband providers DNS Server IP?
Is this view correct or should all router users always enter 192.168.0.1 as primary DNS server?

Assume I enter another external DNS server (like OpenDNS or GoogleDNS) in the Win 7 LAN settings.

When is this second DNS server called? Only then when the first shows no response (=in case of failure)?

Or are DNS requests always broadcasted to both defined DNS servers and Win 7 waits for the faster response of them?

That would produce overhead traffic.

Peter

 

[ChatGPT]

Setting up DNS servers for your LAN can impact how your devices resolve domain names. Let's address your queries step by step: 1. Router IP (192.168.0.1) as DNS Server: - It's common to set the router's IP (192.168.0.1) as the DNS server in LAN settings. The router often acts as a DNS proxy, forwarding DNS requests from devices on the LAN to external DNS servers provided by the ISP. - While the router may not have a robust caching DNS server, by setting it as the DNS server for your devices, it can handle the DNS resolution and reduce the load on external DNS servers. 2. Using External DNS Servers: - You can also manually enter external DNS server IP addresses (like OpenDNS or GoogleDNS) in your Win 7 LAN settings. This bypasses the router for DNS resolution. - By directly specifying external DNS servers, you may potentially get faster and more responsive DNS resolution, especially if the external DNS servers are efficient and reliable. 3. Order of DNS Servers: - In Windows 7, when you enter multiple DNS server addresses, the primary server is typically used first for DNS resolution. If the primary server fails to respond or resolve the domain, only then does the secondary DNS server come into play. - Windows doesn't usually broadcast DNS requests to all defined DNS servers simultaneously. It follows a sequential order, querying the primary server first and moving to the secondary server only if needed. 4. Network Overhead: - Using multiple DNS servers can potentially increase network overhead, especially if the primary DNS server is slow to respond. However, this overhead is generally minimal compared to the benefits of having a backup DNS server in case of primary server failure. In summary, while setting the router's IP as the primary DNS server is a common practice and can provide efficient DNS resolution within the LAN, configuring external DNS servers directly on your Windows device can offer faster and potentially more reliable DNS resolution. Just be mindful of how you prioritize and use multiple DNS servers to ensure optimal performance.