Address Resolution Protocol is a layer 2 networking protocol used for resolving layer 3 addresses (such as IP addresses) into layer 2 addresses (such as Ethernet MACs). It is used by network devices when communicating with devices on the same layer 2 network.

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ARP discovery on multiple subnets

I have an unmanaged switch which serves traffic belonging to different subnets. Lets say these are the subnets: 192.168.0.0/24 192.168.1.0/24 192.168.2.0/24 And few more subnets which I am not aware ...
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Pinging an interface of same network on same host not working

I'm setting up a very basic IPS test, and wondering if an interface on a host pings an interface with a different IP address (of same network) on the same host, will it reply? Will it respond to ARP ...
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iPads cause arp-scan duplicate reports, why?

I have a situation like this: Isolated Gigabit Ethernet LAN with a handful of Linux boxes and Macs on it Airport Extreme wireless access point is also connected to the LAN Two iPads talking to the ...
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Multi-NIC Linux machine's NICs are responding to each other's ARPs regardless of arp_filter setting

I have an old Linux machine running a 2.4.37 kernel. In the machine are two NIC cards both on the same network with different IPs. For some testing, we want each IP's traffic routed through that NIC, ...
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Sporadic routing(?) issues

We are running several virtual machines using KVM with libvirtd with a routed network (the host systems routes an extra subnet for the virtual machines). Host and Guest OS is Gentoo (host on amd64, ...
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Solaris does not record MAC address in ARP table

I have noticed that a Solaris 9 server keeps sending ARP requests for an IP address that is owned by our DNS server. The DNS server answers with its MAC address but Solaris 9 does not record the ...
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How to test 10 gigabit Intel X520 on Ubuntu

I got Intel X520 and connected it to PCI-E x16. The card is recognized as 10 Gbit by ethtool: # ethtool eth5 Settings for eth5: Supported ports: [ FIBRE ] Supported link modes: ...
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Direct server return, ARP problem

I'm trying to implement Direct Server Return scheme for our web cluster and I think i got stuck with some ARP issues. For testing purposes I deployed 2 virtual servers (inside ESXi environment). Host ...
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arp table filling up

I have a CentOS 5 system which serves as an IPSec VPN connector between my network and a couple of remote networks. Lately it is running into this problem once or twice a day where its ARP cache gets ...
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how can I stop my sonicwall TZ-210 (SonicOS Enhanced 5.5.1.0-5o) from responding to arp queries on the wan subnet?

My sonicwall TZ-210 is answering arp queries on the wan subnet (which my isp doesn't like), basically mapping all the wan ips to its own mac address, causing network havoc since it is not set to route ...
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Is there a config file for ubuntu server like /etc /ethers to config the mac-ip bind?

i can't find /etc/ethers in ubuntu server:< i want save something like "sudo arp -s someipaddress macaddress" so i don't need to set it again after reboot
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Is there a way to disable outgoing ARP requests on the wan interface on a sonicwall TZ 210

My internet provider is having a lot of trouble with excessive ARP requests coming from a sonicwall TZ-210. I need to tell the sonicwall not to send so many or to send no ARP requests at all from the ...
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523 views

Hardware won't respond to each others ARP requests

I have two pieces of hardware (embedded devices) that I have setup to communicate via TCP over Ethernet in a client/server fashion. The topology of the network is as follows: ----- | S ||=|== Debug ...
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Is a low-bandwidth arp-scan potentially disruptive to persistent TCP connections on the same LAN?

First a little background: On the (isolated) /16 LAN in question, we have several devices that keep several persistent TCP connections open between them. The program at each end of these TCP ...
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Is this how ARP works? [closed]

A wants to send a datagram to B. A knows B's IP address. However B's MAC address is not in A's ARP table. So A broadcasts an ARP query packet to all machines on the LAN. B recognizes it's IP, so it ...
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6answers
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Windows 2008 ignores Gratuitous ARP requests

We recently saw an issue after a fail over of our router where our Windows 2008 Boxes didn't start talking to the primary router after fail-back. When we did some digging they still had the ARP ...
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How to find the process which causes the arp request?

When i run tcpdump in the gateway, i get a lot of arp requests originating from the gateway itself. I wonder know why this happens. How can i find the process that causes these arp requests? $ ...
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ARP request are sent even though windows has an entry in cache (ARP Table)

we have a product which runs on windows XP embedded SP1. We add a fake(does not exists) MAC address for a fake IP in ARP table. When there is a communication happening Windows sends packets to the ...
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What would cause a Windows 2008 server to switch destination MACs in the middle of a TCP session?

My Windows 2008 server started a TCP session talking to one destination mac address, but in the middle of the TCP session started sending packets to another destination mac address and then eventually ...
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551 views

Effects of having a rapid ARP flush

So the scenario is we have a web server at our colocation. In front of that web server are two SonicWalls and two L2 non-stacking managed switches. We're trying to find an efficient way to set up ...
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Linux is not sending arp request

We have a local network that is connected to internet through linux gateway. There are about 50 workstations in LAN. We recently started observing a problem that gateway sporadically stops responding ...
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Need confirmation on layer 2 security question

I need confirmation on a question regarding layer 2 security. I've been doing research and I just need to know that I understand it correctly. Basically, if you have a LAN with a few machines ...
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ARP replies contain wrong MAC address

I've got a robot running linux with wired and wireless adapters. When I boot up, it connects to the wireless fine. When I assign an IP to the wired (either statically or with DHCP), it looks like it ...
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1answer
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Is it possible to disable ARP in Windows 7

I have a unique requirement where I need to disable ARP on a Windows 7 box. In previous Windows versions you could modify the ArpRetryCount in the registry (and set it to 0), but this does not work in ...
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Windows 2008 R2 Servers Sending Arp Requests for IPs outside Subnet

By running a packet capture on my my routers I see some of my servers sending ARP requests for IPs that exist outside of its network. For example if my network is: Network: 8.8.8.0/24 Gateway: ...
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Clear arp cache

How to clear arp cache ? How to refresh arp table ?
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No answer on arp requests?

I have a problem where my Layer 3 Dell PowerConnect 6248 Switch (main switch) will sometimes (that means sometimes it works, sometimes it won't) not get an arp response from a device behind Dell ...
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Same native and tagged vlan possible on Redhat?

I'm looking at implementing a systems using a number of tagged and a native vlan connected to a server over a a/p bonded interface. The untagged vlan is for physical machine access, the tagged vlans ...
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Ettercap - packet injection / alteration

So I have a proxy setup using squid on port 3128. I also have ettercap setup. My main goal is to change data as it flows through my proxy. Basically, you open up www.something.com using my ...
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Why my laptop sends ARP request to itself?

I have just started to learn about protocols. While studying the packets in wireshark, I came across a ARP request sent by my machine to my own IP. Here is the details of the packet : No. Time ...
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5answers
915 views

Computers on one subnet can't connect to the internet

I have an issue with my student computers - they can't connect to the internet. Here's the weird part: I open a command prompt and ping our gateway server, and suddenly everything is fine (at least ...
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Is it possible to use proxy-arp back to the same interface?

I have a WiFi Access Point connected to a Linux Router. The Router is itself connected to the Internet. For multiple reasons (mostly to control security and quality of service), I want to force all ...
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ARP packets never routed?

is it true ARP only works in single broadcast domain and arp packets are not routed frm 1 network to another ? can any one give me any example or any source of info for this hoping for positive ...
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Linux bridge responding to arp on wrong interface?

I'm trying to build a silent bridge for monitoring purpose. My computer is running linux 2.6, brctl 1.4 and has 3 NIC: eth0, with an assigned IP, used for SSH maintenance eth1, and eth2 , the 2 ...
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CISCO: ARP Poisoning Countermeasures

How can I prevent the Cisco Catalysts 2950/2960/3550/3750 from being vulnerable to ARP Poisoning? Can this be avoided with the ARP INSPECTION? Thanks
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Using arpwatch to backtrack proxy access ip to eap-tls certificate

In my network I am using eap-tls authentication (machine certificates) for clients. Those clients are using a squid proxy to access the internet. The proxy is logging the request to the access.log. ...
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How are ARP reply collisions typically handled?

If a node receives multiple, conflicting ARP replies, what happens?
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Clearing ARP cache on ESXi 4.1

We recently migrated our entire VMware cluster from ESX over to ESXi. For the most part, the transition was seamless, and I haven't missed having access to the SC. Until now. We're trying to diagnose ...
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arp result interpretation

So what does the command arp -a do? I've been told it displayed the MAC addresses of all network cards on the computer, but when I ran it, it displayed three MACs for three IPs (192.168.41.1, .6, and ...
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Is there a way to trace what's sending gratuitous arps?

We have a box that's just started acting up and we're not really sure why. It has IP address (dummy examples) 199.199.199.1 on eth0, 127.0.0.2 on eth1, and 199.199.199.2 on eth1:0. Recently, for some ...
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Software to Generate False ARP Requests?

A product I'm testing appears to freak out when it receives an ARP request with a Sender IP Address of 0.0.0.0. This is not an ARP probe, as the request is addressed to my module, and the customer's ...
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603 views

Two NIC's in the same ip segment

What is the best technical solution to solve this? I have a /24-segment with two NIC's in one Linux Server (lets call it srv) that have two IP-addresses in this segment. NIC1 / eth0 / 10.10.1.101 / ...
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How to broadcast ARP update to all neighbors in Linux?

Some clients in the subnet has cached the IP with old MAC address, I want them to update the new value by doing a ARP broadcast, is it possible in Linux?
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How to configure remote access to multiple subnets behind a SonicWALL NSA 2400

I have a client that uses a SonicWALL NSA 2400 as their firewall. I need to setup a second LAN subnet for a handful of PC. Management has decided that there should be a second subnet even though ...
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No ARP reply on tap0 (KVM bridged networking)

I wanted to assign an external IP address to my KVM guest and went the bridged networking way. Unfortunately the guest has no network connectivity and I don't know why. After investigating it seems ...
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arp failing after heartbeat failover occurs

I have an LVS based load balancer which has been working just fine. It runs on two servers using heartbeat to provide failover. I've added support for a second IP range to the system, but when the ...
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How to prevent response to who-has requests on virtual eth interface?

we use small embedded X86 linux servers equipped with a single physical ethernet port as a gateway for an IP video surveillance application. Each downstream IP cam is mapped to a separate virtual IP ...
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How to stop my VPS from picking up ARP reqs it is not supposed to?

Machine: Xen-3.0 image running stable Debian Linux 2.6.18, pretty vanilla. My VPS provider asks me to deal with some trouble my image is causing, namely handling IP addresses it is not supposed to: ...
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Bypassing VLAN with known MAC address

I am evaluating subneting our network with a Layer 2 switch and VLAN. From what I know, VLAN only works on broadcast domain, and if I know the MAC address of a remote computer on the same switch, I ...
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Wireshark arp packets

In wireshark, after capturing some arp packets, what is the significance of all 1's in the destination field. of an Ethernet II frame?