Answer / jerald

Proxy ARP (RFC 1027) is a way to make a machine physically
located on one network appear to be logically part of a
different physical network connected to the same
router/firewall. Typically it allows us to hide a machine
with a public IP address on a private network behind a
router, and still have the machine appear to be on the
public network "in front of" the router. The
router "proxys" ARP requests and all network traffic to and
from the hidden machine to make this fiction possible.

Consider a router with two interface cards, one connected
to a public network PUBNET and one connected to a private
network PRIVNET. We want to hide a server machine on the
PRIVNET network but have it accessible from the PUBNET
network. The IP address of the server machine lies in the
PUBNET network, even though we are placing the machine on
the PRIVNET network behind the router.

By enabling proxy ARP on the router, any machine on the
PUBNET network that issues an ARP "who has" request for the
server's MAC address will get a proxy ARP reply from the
router containing the router's MAC address. This tells
machines on the PUBNET network that they should be sending
packets destined for the server via the router. The router
forwards the packets from the machines on the PUBNET
network to the server on the PRIVNET network.

Similarly, when the server on the PRIVNET network issues
a "who has" request for any machines on the PUBNET network,
the router provides its own MAC address via proxy ARP. This
tells the server to send packets for machines on the PUBNET
network via the router. The router forwards the packets
from the server on the PRIVNET network to the machines on
the PUBNET network.

The proxy ARP provided by the router allows the server on
the PRIVNETnetwork to appear to be on the PUBNET network.
It lets the router pass ARP requests and other network
packets in both directions between the server machine and
the PUBNET network, making the server machine appear to be
connected to the PUBNET network even though it is on the
PRIVNET network hidden behind the router.

Identify the 3 methods routers learn paths to destinations? A.) Dynamic routing B.) None of the above, configured by default C.) Default routes D.) Administrative distance E.) Static routes

1 Answers  

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hi shyam i am putting urs question here I am facing one problem in my layer 2 switch I don’t know the problem is on switch side or client side. The problem is some PC (not all) are stop participate in LAN they don’t send or recd. Packet from switch and if I check RJ45 (with LAN tester)from PC side the packet and 8 pin wire is working fine and after that process of LAN tester I plug RJ 45 in PC now PC start recd/ send packets what is the problem I don’t understand even client side no virus found RJ45 is ok and switch has no problem bcoz other PC is working fine Cable (cat 5 ) is also fine bcoz I didn’t crimp again just check in LAN tester and start working fine. Plz any one solve this matter. And after lan tester process pc is working fine and after 2 or 3 hour it again start same problem and again same process lan tester I have used

1 Answers   IBM,

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Which configuration task must you complete if a remote Frame Relay router does NOT support Inverse APP? A.configure static maps B.define an IP address locally C.disable DHCP on the Frame Relay router D.configure a static route to the remote network

1 Answers  

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Identify 2 characteristics of PPP? A.) Uses LLC to establish the link B.) Default serial encapsulation C.) Support multiple layer 3 protocols D.) Offers two types of authentication; PAP and CHAP

1 Answers  

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what is ip address?

3 Answers   HCL,

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1. What is an advantage to LAN segmentation? A. Provides multiprotocol support B. Decreases security C. Decreases broadcasts D. Increases broadcasts

2 Answers  

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How does PPP use LCP for link control?

0 Answers   CCIE,

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NetWare IPX addressing uses a network number and a node number. Which statements are true? A. The network address is administratively assigned and can be up to 16 hexadecimal digits long. B. The node address is always administratively assigned. C. The node address is usually the MAC address. D. If the MAC address is used as the node address, then IPX eliminates the use of ARP.

1 Answers  

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What do the following statements in an extended access list accomplish? access-list 101 deny TCP 172.16.4.0 0.0.0.255 172.16.3.0 0.0.0.255 eq 21 access-list 101 deny TCP 172.16.4.0 0.0.0.255 172.16.3.0 0.0.0.255 eq 20 access-list 101 permit TCP 172.16.4.0 0.0.0.255 0.0.0.0 255.255.255.255 A. This will block ftp traffic. B. This will block http traffic. C. This will permit ftp traffic. D. This will permit tftp traffic.

1 Answers  

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What is the Difference between Switch and Bridge?

9 Answers  

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What is the maximum value of administrative you can use?

0 Answers  

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In which access- list type you can't do editing?

0 Answers  

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