15. IP Services Flashcards
What is the reason that time is synchronized between network devices?
- Managing password
- Encryption key changes
- Checking validity of certificates
- Correlation of security based events
- Troubleshooting network devices
What is NTP?
Network Time Protocol UDP 123
What concept does NTP use?
Concept of Stratum.
Server connected to the clock is Stratum 1
Clients connected to the server –> Stratum 2 etc
What is the maximum number of Stratums?
15
What are the command to activate ntp?
ntp master 1
ntp server ip
What is root dispersion?
The calculated error of the actual clock attachted to the atomic clock
What is the Stratum preference
The device with the lowest Stratum is preffered
What are the 3 types of FHRP?
- Hot Standy Routing Protocol
- Virtual Router Redundancy Protocol
- Gateway Load Balancing Protocol
What do FHRP do?
The create a virtual IP
What is object tracking?
Mechanism for linking with FHRP. Users can track specific objects in het network.
What is Hot Standy Routing Protocol?
Cisco protocol for redundancy for IP hosts on ethernet networks. Works with active and standby
What happens when an active HSRP router fails?
The standby router takes over with the virtual IP and virutal mac
How does the HSRP election goes?
Based on highest priority (default 100)
With tie –> highest IP
How many HSRP version are there?
2
v2 supports millisecond timer values
What are the HSRP multicast addresses?
- 0.0.2
224. 0.0.102
What are the HSRP mac addresses?
- 0C07.AC..
0000. 0C9F.F000 –> .FFFF
What is Virtual Router Redundancy Protocol?
- Works with master router and back up routers
- Preemption by default
- 2 versions V2-V3 ipv6 included
What are the VRRP multicast addresses?
224.0.0.18
What are the VRRP MAC addresses?
0000.5500.01..
What is Gateway Load Balancing Protocol?
Cisco protocol
What are the two roles of GLBP?
AVG - max 1 per group
AVF - max 4
What are the 3 supported ways of load balancing?
- Round robin (default)
- Weighted
- Host dependent
What are the 4 terms of NAT?
- Inside local
- Inside global
- Outside local
- Outside global
What is inside local?
The actual private IP assigned to a device
What is inside global?
The public IP that represents one or more inside local IP addresses to the outside
What is outside local?
The IP address of an outside host as it appears to the inside network
What is outside global?
The public IP assigned to a host on the outside network
What are the 3 types of NAT?
- Static - one-to-one
- Pooled - dynamic one-to-one
- PAT - dynamic many-to-one
What is the default timeout for NAT translations?
24 hours
What are the 2 security concepts of NTP?
- Access list based restriction schemes
- Encrypted authentication mechanism
