What is the Limited Broadcast Address in IPv4?
Limited broadcast address is 255.255.255.255. Packets sent to this address are broadcast to all hosts on the local network and are never forwarded by routers.
Which loopback address is reserved in IPv4 for local inter-process testing?
Class A network 127.0.0.0/8 is reserved for loopback. 127.0.0.1 is standard localhost loopback address.
An IP packet with Total Length = 4000 bytes and IHL (Internet Header Length) = 5 arrives at a router. If MTU = 1500 bytes, into how many fragments will the packet be split?
IHL = 5 words = 20 bytes header. Data length = 4000 - 20 = 3980 bytes. MTU = 1500 bytes (1480 bytes max payload per fragment since payload must be multiple of 8). Frag 1: 1480 B payload + 20 B header. Frag 2: 1480 B payload + 20 B header. Frag 3: 1020 B payload + 20 B header. Total 3 fragments.
In IP packet fragmentation, what value is stored in the Fragment Offset field for the second fragment carrying bytes 1480 to 2959 of original data payload?
Fragment offset is measured in units of 8-byte blocks. Offset = 1480 / 8 = 185.
Which field in the IPv4 header prevents packets from circulating indefinitely in routing loops?
Every router decrements the TTL field by 1. If TTL reaches 0, the router drops the packet and sends an ICMP Time Exceeded message to the source.