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28 Cards in this Set
- Front
- Back
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What does NAT stand for?
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Network Address Translation
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What does NAT do?
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Maps Private IP address to Public IP address.
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What are 3 Benfits of NAT?
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- connect pools of private IP addresses to 1 external public IP address.
- hides your inernal IP addressing scheme from the outside world. - Allows for easy renumbering of your IP addresses (If you change ISP) |
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what are the disadvantages of NAT? (2)
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-small amount of delay into network because the NAT router has to create and maintain the NAT table.
- some application fail due to NAT |
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what are the 3 available forms of NAT?
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- Static NAT
- Dynamic NAT - Port Address Translation (PAT) |
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How does Static NAT work?
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single private IP address is mapped to a single public IP address
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How does Dynamic NAT work?
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Automoatically connects public addresses to private addresses
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what is PAT also known as?
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overloading
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What does "PAT" mean?
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Port Address Translation
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How does PAT work?
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Allows multiple internal, private IP addresses to use a single external registered address.
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what is a socket?
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combination of the IP address and Port
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what is overlapping?
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occurs when the internal netowrk has been incorrectly configured for an IP range that actually exist on the Internet or when two companies merge and each company was using the same private IP address range.
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what is the command to conifigure Static NAT?
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ip nat inside source static [inside ip] [outside ip]
(define outside & inside interfaces): ip nat inside ip nat outside |
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what command shows static nat mapping?
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show ip nat translations
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what is the syntax for defining a standard access list?
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router(config)#access-list [1-99] permit [inside IP network] [wildcard mask]
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what is the syntax to define a NAT pool?
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ip nat pool [pool name] [start ip] [end ip] netmask [netmask]
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what is the command to link a NAT pool to an Access List?
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ip nat inside source list [access list number] pool [pool name]
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what is the syntax to finalize a dynamic NAT?
(define the int) |
(config)#int f0/0
(config-if)#ip nat inside (config-if)#int serial 0/1 (config-if)#ip nat outside |
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What are the 3 steps to configure NAT?
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- Configure a standard access list to define what internal traffic will be translated.
- Link the access list to the interface to be used with PAT - Define interfaces as either insdie or outside |
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what does "DNS" mean?
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Domain Name Service
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what does DNS do?
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Translates names into IP addresses
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What command would you use if you wanted to disable name lookup broadcast on a router (usually because of typos)
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no ip domain-lookup
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What is the command to enable DNS if it has been disabled?
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ip domain-lookup
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what is the command to configure DNS lookup?
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ip name-server
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what does DHCP stand for?
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Dynamic Host Configuration Protocol
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What does DHCP do?
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DHCP manages addressing by leasing the IP information to the hosts
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what are the command to configure DHCP on a router?
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RouterA(config)#ip dhcp pool Router A
Network 10.0.0.0 255.255.255.0 default-router 10.0.0.1 dmain-name cannon dns-server 10.0.0.3 netbios-name-server 10.0.0.3 ip dhcp excluded-address 10.0.0.1 10.0.0.3 |
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what is a command to monitor or check DHCP status?
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show ip dhcp binding
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