2.10 - Implement IP version 4 (IPv4) addressing, subnetting, and variable-length subnet masking (VLSM) Flashcards
What is the maximum possible size of an IP Packet?
65,535 octets
What IP addresses are in the Class A range?
0.0.0.0 - 127.255.255.255
What IP addresses are in the Class B range?
128.0.0.0 - 191.255.255.255
What IP addresses are in the Class C range?
192.0.0.0 - 223.255.255.255
How can you determine a Class A address in binary?
The left most bit of the entire 32-bit string is always 0
How can you determine a Class B address in binary?
The left most bit of the entire 32-bit string is always 1 and the second bit is 0
How can you determine a Class C address in binary?
The first 2 bits of the entire 32-bit string are set to 1 while the third bit is 0
What IP addresses are defined by RFC 1918
10.0.0.0/8, 172.16.0.0/12 & 192.168.0.0/16
How do you enable proxy ARP?
router(config-if)# ip proxy-arp
How do you disable proxy ARP?
router(config-if)# no ip proxy-arp
What is the default age of ARP entries on Cisco devices?
Four hours (14,400 seconds)
What is the command to change the ARP timeout on a Cisco device?
router(config-if)# arp timeout
What is the command to enter a static ARP entry on a cisco device?
router(config)# arp
What is the command to clear the ARP cache on a Cisco device?
clear arp-cache
Describe proxy ARP.
Sometimes called promiscuous ARP, it allows a router to pose as a device on a connected network and reply to devices that do not have default gateways set.
Describe gratuitous ARP.
An ARP request sent with the senders IP address in the target address field.
Describe IP redirects.
Used to tell hosts to use a different gateway to reach an IP address.
What ICMP type is a redirect?
ICMP type 5
How do you disable IP redirects?
router(config-if)# no ip redirects
What fields in the IP header are used for fragmentation?
Flags and fragment offset
What is TTL?
Time to Live
How is TTL calculated?
Every router decrements the value by one, once value reaches 0 the packet is discarded.
What command changes load sharing to be by destination on a cisco router?
router(config)#ip load-sharing per-destination
What command changes load sharing to be by packet on a cisco router?
router(config)#ip load-sharing per-packet
