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Flashcards in Network Services Deck (14)
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What are the four steps in a DHCP exchange

DORA: Discover Offer Request Acknowledgement


How do you set an interface to use DHCP

ip address dhcp (activate by restarting the interface)


How do you configure a router to become a DHCP server

ip dhcp pool pc IP address / subnet mask
make sure to provide default router interface


What are a few properties of HSRP

A Cisco proprietary first hop redundancy protocol
Essentially, a host has a default gateway to get off a subnet but if the router goes down, the pc cannot connect outside of their subnet
As a result you can connect the host to many other "routers"/layer 3 switches such that if one goes down the other one can be operated: both switches in active mode have IP address and Mac address of virtual router


What if the interface of a router/layer3 switch goes down?

A feature called interface tracking can monitor an interface then dynamically change the priority of the switch


What is an active router and what is the default priority

An active router is the router with highest priority and the default priority is 100.


What if a router/layer 3 switch goes down or breaks?

The other backup router will know via hello messages not send after the hold time that the router has broken down


What does preempt do?

If a router is initially up but breaks and then goes back up, it can restore its position as the active router because it had an initially higher priority


Set up two routers with HSRP

standby (group number) ip (virtual address)
standby 10 priority (priority)
standby 10 preempt

trace route


How do you see which router is the active router within HSRP

show standby brief


What versions of HSRP support what IP

HSRP version 1 supports only IPv4 HSRP version 2 supports IPv6


What is a stratum number

The believability of a time source


What is a highly believable stratum number



How does stratum number change across devices

each device adds one to the stratum number from the device they learn it from