Red Rozenglass on Nostr: pwm The routing table tells the OS where to send a packet depending on the address ...

pwm (nprofile…a0fc) The routing table tells the OS where to send a packet depending on the address it's meant to. It does something similar to zip codes in postage. For example, if you have a packet meant for Google's IP, the routing table may tell your OS to send the packet not to Google's IP, but actually to your WiFi router's IP. Thus, the routing table basically helps you delegate the actual delivery of a TCP/IP packet to some other network actor that actually knows what to do next.

I may want for example all my packets meant for the internet to go instead to my VPN server, because my VPN server will handle further delivery. So, I may set my VPN server's private IP as the default gateway in my routing table. But maybe I want to use some local network stuff, and my VPN server wouldn't know how to handle my local server, so my routing table would set my local router to be the destination if the packets are meant for local network IPs, I may have some work network that is handled by a different VPN, so work IPs get routed through that other VPN server, etc.

For your packet to reach its final destination, it is likely being routed by a dozen routers between you and your target server. Each of those intermediate servers is consulting its routing table to decide where to send the packet next, until, finally, the packet reaches a server that has Google's actual IP address in its routing table (think final postman when sending cargo). You can see this happening in real-time using software tools like "traceroute".