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MAC address are used for uniquely identifying my computer.
IP address are used for routing the packets to the network, as it has got a hierarchial structure, but it doesn't uniquely identifies a computer. So, after IPv6, each computer will have a unique IP address, so will there be any need of MAC address then?
Please do correct me, if I had understood something wrong.
No. MAC addresses operate at layer 2 ("data link layer"). The Internet Protocol (both IPv4 and IPv6) operates at layer 3 ("network layer").
These two layers are complimentary, and do not "replace" each other. For more information, read up on the TCP/IP suite.
IPv6 stateless address autoconfiguration (SLAAC) uses the MAC address to generate the address, but that does not mean they "replace" each other. It's simply a characteristic of the layer 2 interface being inherited by the layer 3 addressing. Other than that, completely complimentary.
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I have a HP ProCurve switch, I recently added 2 new machines to the network, which I had to assign the IP addresses to manually. Now using these 2 machines I can ping my current machine and other machines on the network, however if I try to ping those 2 machines from my current machine (or others on the network) it does not go through. So my thoughts are that the router table has not updated so that's why I can't ping them from machines that have been on this router.
(Not too sure, not enough knowledge yet)
At least I think so. My question is does the Router Table update it's information automatically?
Assuming your HP Procurve is acting only as a switch, then the Routing Table should not be your problem. A switch does not route IPs, a switch is concerned with routing packets via their layer-2 addresses (MAC addresses). The switch determined which physical port is connected to a device with a MAC address, and when it gets a packet addressed to that MAC address, it sends the packet out that port. The mapping on port to destination mac address is stored in a CAM table inside the switch. This is very different from a routing table that maps IP address ranges to physical interfaces.
What is probably happening is that ARP is not resolving. ARP binds layer 3 IPs to layer 2 MACs in a local network. This can be cause for a few reasons. The first thing i would look into is if the switch has VLANs enabled. This makes the switch act like multiple isolated switches. After that you may need to look at your computers ARP tables to make sure they are correct. The arping command will be useful.
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I've a simple question about IP and MAC.
Lets say we have two LANs, A and B, connected by a Bridge (no Network Layer). We have host 'X', which sends an IP packet to host 'Y'. It will send it through a MAC frame. The Payload of that MAC Frame will be our ip packet.
The question is: since X doesn't know Y's MAC Address, which MAC Destination Address will be used in the Frame's Header?
Thank you for your time.
If the X doesn't know the MAC address of Y it will first send an ARP request to ff:ff:ff:ff:ff:ff (broadcast) requesting the MAC address for the IP address of Y. Y will respond with it's MAC address which X will then use as a destination MAC address to send the frame.
Btw, since the bridge is in between they're actually on the same LAN, not A and B.
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I understand that a router uses NAT to translate the public IP we get from the ISP to say 300 local IPs. Does a switch perform the same function? If not, how's it different?
No, a switch cannot perform NAT and translate public(s) IP addresses into private addresses.
A switch is a network device that filters and forwards packets between LAN segments. Switches operate at the data link layer (layer 2). So, they are not aware of IP addresses which are network layer (layer 3). A switch keeps a record of the MAC addresses of all the devices connected to it. With this information, a switch can identify which system is sitting on which port. So when a frame is received, it knows exactly which port to send it to, without significantly increasing network response times.
Routers are network devices used to interconnect two different networks (with different IP addressing schemes).
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whats the purpose of local IP addresses if there are mac addresses? ARP maps mac addresses to IP addresses but I don't see why it's needed, because I thought data on LANs are sent as frames which only care about the mac addresses.
Long ago and far away, there was more to the world than Ethernet LANs, and application writers didn't care whether your PC was attached to an Ethernet, a Token Ring, an XNS net, or dial-up. IP provides a layer of abstraction and coherence across the top of all those and many more, allowing application authors to ignore the differences between them.
And what happens if you want to talk to a macine that isn't on your local area network (such as StackOverflow).
IP allows routing of packets anywhere, not just locally in your current network segment and, though it's mostly over Ethernet now, IP can equally well work over other underlying layers, giving a consistent view to the upper layers. This is vital given how much stuff is actually built on IP (DNS, FTP, SSH, HTTP and so on).
Machines almost certainly will cache IP-to-ethernet details to speed up subsequent transfers so the impact of translation on the LAN isn't so bad.
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At my current place of employment, on my Windows box, when I do an ipconfig /all from my command prompt I see that I have both a static IP address as well as a dynamic IP address. Why could that be? I am trying to diagram our network structure for a new software project that I'm on...knowing the answer to this question could help out a lot.
You have multiple NICs and are multi-homed?
These are from different interfaces. You could be on a VPN, have a wireless connection, or have 2 network cards.
One possible reason is if you need to have multiple host names/IPs for a computer with a single NIC. See this link for more information. Personally I can't see why this would be necessary, but it seems that Windows does provide a means to do it anyways.