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1500 questions
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3 answers

Alternatives to multiple Service Providers

I have one SP right now that serves 100 Sites and we are currently planning to migrate all the sites to a new SP. However, this will be a phased migration, so we will have some sites in the new SP cloud and others in the old one. The SPs will not be…
Brown Taylor
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Position of source and destination IP in an IP packet

In an Ethernet frame header, the destination MAC (DMAC) is placed before the source MAC for obvious reasons (stations accept based on DMAC). But why is not the same thing maintained for destination IP (DIP) and source IP (SIP) in the IP Header? Why…
john
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4 answers

what is the difference between a CSU/DSU and a modem?

I'm so confused, both do the same function, converting the analog to digital, but what's the difference?
ahmad fakeer
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Why is the NDP Neighbor Solicitation message sent to the solicited-node address?

As I understand it, when Host Alice knows Host Bob's IPv6 address but not its MAC, Alice sends an NDP Neighbor Solicitation (NS) message to the solicited-node multicast address for Bob. Alice knows Bob's unicast address, so why send the NS to a…
Jacktose
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4 answers

Check all the active IP addresses on a switch

I have a small LAN network. Each table has a switch, and the laptops are connected to that switch. There is a host which is using a large amount of the Internet bandwidth, and I would like to find out which one. I have that user's IP address (the…
tranmaster
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4 answers

How can hosts on two different VLANs communicate?

It is clear that hosts on two different VLANs can't directly communicate on a single switch, but how do they communicate to each other at all? Do they use a router? How does it work?
ds459
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7
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How is Multicast IP mapped to Multicast Mac address?

My main concern is why is the address 01-00-5E- and how? Especially 5 and E??
user3156370
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Problem with remote access, fixed L2L and dynamic L2L IPSEC working together on ASA 5540 8.2

I have an issue with a mixture of remote access, L2L and dynamic L2L tunnels on an ASA5540 running 8.2 Here is a snip of the relevant config:- crypto dynamic-map outside-crypto-dynamic-map 10 match address outside-crypto-dynamic-map-10 crypto…
aleks
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7
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Establishing IP DHCP Snooping

Have establsihed a lab to test IP DHCP SNOOPING prior to implemntation. So far everything works as advertised. Given that the Uplink port of a switch must be trusted, why is it not necessary to add the trust to a access point?
rsebastian
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Tacacs VRF authentication

We just got a new Supervisor7 with os 3.4.1. I'm trying to configure authentication with tacacs, and I can't understand how to make it work. This configuration works on our other switches, but it doesn't work on this 4500. aaa new-model username…
Nachos
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7
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1 answer

Nexus 1000V HA with appliance and VM

Can you make an HA pair out of an actual Nexus 1110 appliance vsm and a 1000V VM based vsm in one pair? If so can anyone point to documentation that allows it?
Ken
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2 answers

How do the Telnet requests "DO" and "WILL" differ?

I am implementing a Telnet client using RFC 854. I read about the negotation syntax (DO, WILL, WON'T, etc.) and am confused by this paragraph: In summary, WILL XXX is sent, by either party, to indicate that party's desire (offer) to begin…
cadaniluk
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How do you define an IOS zone-based firewall policy to inspect "any"?

When configuring ZBFW on IOS, the "class-default" class doesn't allow the inspect action (only pass and drop). What is the recommended way to match all traffic for stateful inspection? Matching TCP, UDP, and ICMP seems to work fine, but this doesn't…
Jeremy Stretch
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7
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What would happen to Ping if two PCs have same IP address with same Subnet Mask on same network?

If there are two PCs with same IP address on a LAN, what would happen if I ping that IP address from another PC on the same network and why?
Bhupendra Pandey
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In 802.1Q Tunneling what exactly is meant by "a point-to-point topology before you enable tunneling for PAgP, LACP, or UDLD"

I have one switch that I want to use as an 802.1q tunnel, to make the spanning tree and etherchannel transparent, a pass through switch between a core switch and access closets, because I do not have enough phyiscal cabling to run to the core from…
Garry Baker
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