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Questions tagged [arp]

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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How to get a list of all IP addresses (and ideally device names) on a LAN?

Our network gave an error that there was an IP address conflict and I'd like to find what all the device IP addresses are. (I've also had need of that before). (update/clarification:I'm looking for a Windows-based too.) Any suggestions? I've read…
Clay Nichols
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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 entry from the secondary router. According to the…
Zypher
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Is there any way to ARP ping on Windows?

On Linux and other systems, there is an utility called arping which can be used to send ARP requests ("pings") and show the answers, much like the "ping" utility but using ARP instead of ICMP. Is there any way to do the same on Windows? (I use…
Etienne Dechamps
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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?
Howard
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ARP broadcast flooding network and high cpu usage

Hoping someone here might have some insight to the issue we are facing. Currently we have Cisco TAC looking at the case but they are struggling to find the root cause. Although the title mentions ARP broadcast and high CPU usage, we are unsure if…
Cold T
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Ubuntu Linux - multiple NICs, same LAN... ARP responses always go out a single NIC

We've got AT&T U-Verse internet service, which has an extremely boneheaded DSL gateway. We have 5 IPs (netmask 248), but the gateway is incapable of doing anything other than a single IP -> single MAC address mapping. We have a single firewall…
darron
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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 works. As in, ifconfig shows a proper IP and…
Jayen
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Strange: why does linux respond to ping with ARP request after last ping reply?

I (and a colleague) have just noticed, and tested, that when a Linux machine is pinged, after the last ping it initiates a unicast ARP request to the machine that initiated the ICMP ping. When pinging to a Windows machine, the Windows machine does…
Rabarberski
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Default arp cache timeout

I didn't found how check and change the default arp cache timeout on Linux. I using debian with kernel 3.x (but I supposed it same with older kernels)
Pol Hallen
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arp-requests cannot be seen by specific nodes

I create an open ad-hoc wlan by using iwconfig (I have the same issue with wpa_supplicant as well). there are 4 nodes on the network as seen on the figure below. The nodes run ubuntu 12.04 and debian squeeze, and have 3.7.1, 3.5 and 3.2 kernels. I…
johan
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Machine always responds to 192.168.1.2 IP address, which is not set on the machine

UPDATE BELOW: UPDATE 2 BELOW: FINAL Solution I have a brand new HP EliteBook notebook 8560p running Windows 7 64bit. I plug it into a small Dlink di-604 router, it is currently configured with DHCP and gets ip address 192.168.1.100, ip address of…
ethermal
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What happens when ARP Request comes from a different subnet?

What will happen when an ARP Request packet is sent from router1 to router2 in the following two cases? Will an ARP Reply be generated or the ARP Request packet be dropped? [router1]Intf1(20.0.0.1/24) ======== (40.0.0.1/24)Intf2[router2]…
gsinha
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Keepalived send gratuitous ARP periodically

Is there a way for a keepalived to send gratuitous ARP periodically? We had following situation: switch failure (VLAN setup) keepalived failovered to backup instance backup instance sent gratuitous ARP but Cisco ASA device didn't got it (because of…
user373333
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arp --delete is not deleting an entry; merely marks entry as "incomplete"

$ sudo arp -avn ? (10.10.7.30) at 00:cc:cc:bb:dd:86 [ether] on eth0 ... $ sudo arp --delete 10.10.7.30 $ sudo arp -avn ? (10.10.7.30) at [ether] on eth0 After --delete I expected no entry for 10.10.7.30. Unexpectedly, the entry…
JamesThomasMoon
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Neighbour table overflow on Linux hosts related to bridging and ipv6

Note: I already have a workaround for this problem (as described below) so this is only a "want-to-know" question. I have a productive setup with around 50 hosts including blades running xen 4 and equallogics providing iscsi. All xen dom0s are…
tim
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