Router's DNS settings question
Router's DNS settings question
I didn't locate a clear solution. Your router offers two ways to add DNS servers: one in the "Network" menu and another under DHCP settings. The first lets you choose your ISP's DNS or custom entries, while the second adds DNS through the DHCP server. Understanding the distinction helps avoid confusion when configuring network settings.
I envision the first scenario as configuring forward lookup zones, where the router functions as a DNS server. You can select between the ISP's servers or define alternative servers for requests it doesn't recognize. The second involves assigning DNS servers through DHCP, ensuring clients connect directly to those servers instead of routing queries through the router. Some routers may offer identical settings across different areas, suggesting they're essentially the same function.
The router already knows which DNS servers to use when accessing the internet, such as during updates. The second setting tells the router how to set up DNS servers on devices that connect via DHCP. Usually, you provide the router's IP address for this purpose, allowing it to function as a local DNS cache. This setup means the router must have its own DNS configured so it can forward requests not already stored.
When your router's IP is set as the DNS server in DHCP, all devices on your local network that receive their IP through DHCP will use it as their DNS provider. This method is typically quick (<1ms for DNS queries) since the router is part of your local network. If your router is outdated, an external DNS might perform better. The downside is that many cached DNS servers can delay responses when a server's IP changes. If your router doesn't have the answer, it will send the request to the DNS you configured (like OpenDNS) and store it locally for faster future access.
It seems you're wondering if using your router as a DNS server affects your access to features like Open DNS or phishing protection. The router will still use its assigned IP address each time it changes, so your connection remains consistent unless there are network restrictions in place. If you didn't set anything up, the behavior should match what you'd expect without a custom DNS setup.
It differs because your router stores DNS queries. This means if the site isn’t restricted by OpenDNS at first access, your router will save its IP. It retains that until the cache expires, so it’s likely your router will still fetch the host name briefly afterward. Your setup seems correct. The settings are optional, so it might default to its own IP when left blank. You can test it—it won’t cause issues (clients can’t reach without a gateway/DNS). Just update the config and it should resolve again ("ipconfig /renew").
The cache typically expires after a short period, usually around 5 minutes.