ITPEC IP April 2020 Question 31
When setting up PC1 for connecting it to the Internet, an IP address is set in “default gateway” that is one of the network settings of PC1. Which of the following devices has this IP address?
Explanation
Router — the default gateway is the device on PC1's own LAN that forwards packets on to other networks.
In the figure, PC1, PC2, the DHCP server and one side of the router are on LAN1; the other side of the router, the firewall and the proxy server are on LAN2, and only the firewall connects to the Internet. A packet for the Internet is not for LAN1, so PC1 hands it to its default gateway. That must be an address on LAN1 belonging to a device that forwards between networks: the router's LAN1 interface. The router passes the packet onto LAN2, from where it goes out through the firewall.
Answer (a)
Why not others:
- •(b) Firewall — it sits on LAN2, not on PC1's own network, so PC1 cannot hand packets to it directly; it is where traffic goes after the router
- •(c) DHCP server — it is on LAN1, but it only hands out settings, among them the default gateway address; it does not forward packets between networks
- •(d) Proxy server — also on LAN2; a proxy relays web requests on the client's behalf and is entered in the proxy setting of the browser, not as the default gateway
Key rule: The default gateway is always an address on the host's own network: the nearest router interface leading toward other networks.
Networks · AI-written, may contain errors
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