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Difference between arp and inverse arp

Question: So basically both arp and inverse-arp are L2 to L3 mappings; simple arp: MAC(L2) -----> IP(L3) inarp: DLCI(L2) -------> IP(L3). But by the word "inverse" I read _opposite of_ , thus implying inarp is the opposite of arp. Can someone elaborate...

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Configure DHCP on CISCO router

This post is about configuring a CISCO 2951 router to act as a DHCP server in your network. Task1: Configure R1 to act as a DHCP server and provide all network information to hosts in the LAN dynamically. (R1 and R2 are directly connected via Ethernet)...

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Native VLAN explanation

Question: Can someone explain to me what a native vlan is? How it compares to other types, i.e. management, default, etc. I am having a hard time with the terms. Answer: I am looking at a network with different native vlans across multiple switches. While...

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Cisco SYN FLOOD protection

Question: How could one mitigate SYN FLOOD DOS on Catalyst WS-C3750X-48T-L as it has no control plane protection? Answer: 3750 does have some internally priority on what it prefers to punt when congested, but it's not configurable. So you should rely...

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Open a range of TCP ports in Cisco IOS NAT

Question: ip nat inside source static 192.168.1.10 10.10.10.9 route-map RANGE ! route-map RANGE permit 100 match ip address 102 ! access-list 102 permit tcp host 192.168.1.10 range 3000 3389 any The configuration does not seem to work.. just creates a...

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Help to understand L3 SW

Question: I hope you can help me as usuall , i designed a layer 3 lab contains 4 L3 WS-C3560X-48T-S switches + Vlans , the issue is as the following : i can ping any pc from sw0 to sw1 but i can't which is weird ping any thing else like from sw0 to sw2...

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DTP on VTP domain null

Question: i am studying DTP topic and came across this scenario that needs to be clarified. afaik, initially, trunk can only be formed on negotiated link (DTP) between two switches if VTP domain is the same. http://www.cisco.com/en/US/tech/tk389/tk689/technologies_tech_note09186a0080094c52.shtml...

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VLANs, Trunk and Access ports

VLANs, Trunk and Access ports

Let’s talk about VLANs today. Some time ago a friend of mine made me a question. If two PCs are connected to two different switches and they are in two different VLANs, however, the switches are connected to each other with access ports (each belonging...

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Cisco Router Boot Sequence

Question: can you explain the Router boot sequence in detail ? where is the start-up config, running config, mini IOS, IOS located ? Answer: first of all any router to start working will require operating system, in case of CISCO 2901 router we call its...

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