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What does empty ARP cache indicate?
That the MAC addresses have expired
How long do ARP entries remain in the ARP cache by default?
The default amount of time for ARP entries to stay in the ARP cache is 10 minutes for referenced entries and 2 minutes for entries that are not referenced.
What happens to the ARP cache when a Cisco router is powered off?
Unless there are static ARP mappings, the cache will be cleared when powered off.
What commands do you use to verify the ARP cache on a windows end-system and the ARP table ina Cisco router?
arp -a show arp
How do you obtain mac address of HP Laserjet P2055dn?
Usually you don't need the MAC address directly - except perhaps to improve the documentation in a large network.If you know a device's IP address, you can do a pingcommand; before and after, compare the ARP cache - the one that shows assignments of IP addresses to MAC addresses. In Windows, the steps would be more or less like this:Open a command window arp -d * (this will delete the ARP cache)arp -a (this will show the ARP cache)ping ... (this will connect to the IP address you specify)arp -a (show the ARP cache again. Compare with the previous one.)Usually you don't need the MAC address directly - except perhaps to improve the documentation in a large network. If you know a device's IP address, you can do a pingcommand; before and after, compare the ARP cache - the one that shows assignments of IP addresses to MAC addresses. In Windows, the steps would be more or less like this:Open a command windowarp -d * (this will delete the ARP cache)arp -a (this will show the ARP cache)ping ... (this will connect to the IP address you specify)arp -a (show the ARP cache again. Compare with the previous one.)Usually you don't need the MAC address directly - except perhaps to improve the documentation in a large network. If you know a device's IP address, you can do a pingcommand; before and after, compare the ARP cache - the one that shows assignments of IP addresses to MAC addresses. In Windows, the steps would be more or less like this:Open a command windowarp -d * (this will delete the ARP cache)arp -a (this will show the ARP cache)ping ... (this will connect to the IP address you specify)arp -a (show the ARP cache again. Compare with the previous one.)Usually you don't need the MAC address directly - except perhaps to improve the documentation in a large network. If you know a device's IP address, you can do a pingcommand; before and after, compare the ARP cache - the one that shows assignments of IP addresses to MAC addresses. In Windows, the steps would be more or less like this:Open a command windowarp -d * (this will delete the ARP cache)arp -a (this will show the ARP cache)ping ... (this will connect to the IP address you specify)arp -a (show the ARP cache again. Compare with the previous one.)
What is the reason for ARP cache to be emptied after a few minutes of inactivity with a host and why is it beneficial?
An ARP cache holds dynamic network and mapping information. Delaying the clearing of this cache is that dynamic information or processes can be left in limbo and become non-removable after a period of time.
What is one layer of security that can be applied to ARP cache entries that could aid countering ARP spoofing?
static gateway address
To make arp more efficient computers save recognized mac to ip address mappings on their hard disks in a database known as?
To make ARP more efficient computers save recognized mac to IP address mappings on their hard disks in a database known as ARP cache. ARP is an network layer protocol / third layer protocol. ARP provides mapping between Logical to physical address.
What does arp -s do in command prompt?
it allows you to create a permanent entry in your cache
Explain the ARP utility is used for?
TCP/IP Address Resolution Protocol Utility (arp)(Page 2 of 2) arp Utility Functions To allow administrators to manage this ARP cache table, TCP/IP devices include an arp utility. It has three basic functions, which are invoked using three different versions of the command (which, for once, are the same in UNIX and Windows!): * ARP Cache Table Display ("arp -a"): When the "-a" option is used with the utility, it displays the current contents of the ARP cache table. Each entry in the table shows the IP address and hardware address pair for one device (interface, actually); usually an indication is also given as to whether each entry is static or dynamicThe exact format of the display varies from one implementation to the next; some programs show IP addresses while others show host names, and still others may show both. Some systems default to displaying host names but allow the "-n" option to also be used to force only IP addresses to be displayed and not names. * ARP Cache Table Entry Addition ("arp -s "): This syntax allows an administrator to make a new manual ARP cache table entry that maps the given host name to the specified hardware address. * ARP Cache Table Entry Deletion ("arp -d "): This command removes the specified cache entry from the table. Some implementations allow the addition of another parameter to specify that all entries should be removed from the cache. Additional arp Features Certain versions of the software may also supplement these basic commands with additional features. One common additional option on UNIX systems is the ability to specify a file from which cache table entries may be read, using "arp -f ". This saves a considerable amount of time and effort compared to typing each entry manually using "arp -s". Note also that access to options that cause the ARP cache table to be changed may be restricted by the operating system to only authorized users. This is especially true of the delete function, and especially especially true of the function that allows the entire ARP table to be deleted. J
Explain what the arp utility is used for?
TCP/IP Address Resolution Protocol Utility (arp)(Page 2 of 2) arp Utility Functions To allow administrators to manage this ARP cache table, TCP/IP devices include an arp utility. It has three basic functions, which are invoked using three different versions of the command (which, for once, are the same in UNIX and Windows!): * ARP Cache Table Display ("arp -a"): When the "-a" option is used with the utility, it displays the current contents of the ARP cache table. Each entry in the table shows the IP address and hardware address pair for one device (interface, actually); usually an indication is also given as to whether each entry is static or dynamicThe exact format of the display varies from one implementation to the next; some programs show IP addresses while others show host names, and still others may show both. Some systems default to displaying host names but allow the "-n" option to also be used to force only IP addresses to be displayed and not names. * ARP Cache Table Entry Addition ("arp -s "): This syntax allows an administrator to make a new manual ARP cache table entry that maps the given host name to the specified hardware address. * ARP Cache Table Entry Deletion ("arp -d "): This command removes the specified cache entry from the table. Some implementations allow the addition of another parameter to specify that all entries should be removed from the cache. Additional arp Features Certain versions of the software may also supplement these basic commands with additional features. One common additional option on UNIX systems is the ability to specify a file from which cache table entries may be read, using "arp -f ". This saves a considerable amount of time and effort compared to typing each entry manually using "arp -s". Note also that access to options that cause the ARP cache table to be changed may be restricted by the operating system to only authorized users. This is especially true of the delete function, and especially especially true of the function that allows the entire ARP table to be deleted. J
What is the purpose of an arp request?
The purpose of an arp request is to map an IP address to a MAC address for the link layer to transmit a packet. For example, ARP will get a request to map 1.2.3.4 to a MAC address 12:fd:23:gf .Then ARP will cache the address mapping that next time an arp request doesnt need to happen
