Put Your Gateway on the Right Network

Two causes are common. A gateway left on a factory address such as 192.168.1.100 is on a different network series from the Jio router at 192.168.29.1, so it cannot reach it at all. And on DHCP, the router hands out its own address as the DNS server but does not answer the gateway's name lookups. Use an address in the router's series and set Primary DNS to 8.8.8.8.

Phones and laptops can also look names up over IPv6, and the router answers those. The gateway uses IPv4 only, so it depends on the router answering IPv4 lookups, which some routers never do. A laptop that opens a website is therefore not proof: test with nslookup against the router's address and against 8.8.8.8.

Keep the router's first three numbers and pick a last number outside the range the router hands out by itself (its DHCP range, in the router's LAN settings). Many routers start that range at 100, and some run it up to 249, so check it. Ping the address first: no reply means nobody is using it right now. Surest of all, ask IT to reserve it in the router.

Airtel Xstream Fiber routers usually use 192.168.1.x, the same series as a gateway's factory address of 192.168.1.100, so the gateway reaches the router. Jio Fiber uses 192.168.29.x, so a gateway left on its factory address cannot. On DHCP it gets the right address, but the Jio router hands out its own address as DNS and never answers the gateway's lookups. Use the router's series and set Primary DNS to 8.8.8.8.

It is the usual address of a Jio Fiber router, and so the Gateway (default gateway) setting for every device on that network. Devices there use 192.168.29.something with the netmask 255.255.255.0. Confirm yours with ipconfig on a laptop: it is the Default Gateway line.

A public DNS server such as 8.8.8.8 or 1.1.1.1. Do not enter the router's address. Note that 8.8.8.4 is not a DNS server: Google's are 8.8.8.8 and 8.8.4.4.