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.
Questions tagged [arp]
421 questions
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votes
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Persistent static ARP entries on Windows, is it possible?
I am currently running coLinux configured in "ndis-bridged" networking mode, on a machine whose wireless networking card or driver seems incapable or unwilling to accept non-broadcast layer 2 traffic, or traffic not destined for the wireless card's…

dmw
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Set up bridged vxlan network in linux
I'm trying out vxlan with linux, and this problem has kept me stuck for days.
Simple Vxlan works fine
Simple vxlan with muticast works for cross-host communication, this simply create a vxlan vtep and assign an ip address:
ip link add vxlan100 type…

cizixs
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When wouldn't an ARP reply be generated?
Summary of the problem: a ping from client does not go to rpi1, its ARP call is not answerd at srv.
host0and tap0 are bridged by br0.
vpninand lan0 are two independent interfaces.
All traffic between the interfaces is allowed on srv (IP…

WoJ
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How to find all hostnames (even laptops that aren't currently on the network) on a network?
I manage a network that has a lot of laptops. The users that use the laptops are frequently traveling. When someone gets a new computer I run into a problem determining what the hostname should be. The hostname scheme is [companyname]xxx where…

cwiggs
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Linux bridge not answering arp packets
I'm trying to setup a test scenario regarding linux bridges for which I need a full virtual IP stack. Basically, I'd like to simulate the network between a VM (or container) and its host, just without a VM, i.e. virtualization layer.
The host side…

grasbueschel
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VMXNET3 nic loses the ability to update ARP table after N hours
I have a fedora 18 VM that stops updating the arp table on eth1 after running for a number of hours to days. There are other VMs on the same hypervisor that can access all of the same networks without issue. A tcpdump of the offending NIC shows only…

Peter
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ARP responds with single MAC address on Linux server with multiple interfaces on the same network
Linux server has 2 active network interfaces:
IF:eth1 IP:192.168.1.1/24 MAC:11:11:11:11:11:11 (1GbE)
IF:eth2 IP:192.168.1.2/24 MAC:22:22:22:22:22:22 (10GbE)
The idea is that the 10GbE interface (eth2) is the primary interface for…

sardean
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nmap and arp-scan inconsistent IP-MAC results
I seem to get variable and inconsistent results for the IP/MAC addresses from a particular machine, using nmap or arp-scan.
The machine has 3 interfaces, and this is what it shows:
$ uname -a
Linux showstore-81 2.6.35.13 #1 SMP PREEMPT Thu Feb 9…

mivk
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Same network on different interface
We work with devices that are flashed (factory) using TFTP on a usb network connection.
The server has a fixed 192.168.2.100 address and the device a fixed 192.168.2.101 address. When it starts, it connects to download the firmware.
In the current…

Florent
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Windows Server 2008 ARP Cache Poisioning
Recently ran into a very strange problem.
Several applications were having issues communication through our F5 Load-Balancer. When we looked into it we found that the router had an incorrect ARP and MAC-ADDRESS table entry on the Load-Balancer…

user770395
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tcpdump on interface when pinging nonexistent hosts on local network
I've statically configured the IP address of an interface on a server:
ip addr add 10.40.0.6/16 broadcast 10.40.255.255 dev eth1
If I try to ping a machine on the network (e.g., 10.40.0.1), it fails with "Destination Host Unreachable".
When the…

Lorin Hochstein
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Arp requests with odd source IP go unanswered
I'm having a server with network connectivity issues that I presume come from issues with arp protocol handling.
Let's say the network topology is as follows:
network 192.168.106.0, netmask 255.255.255.0
router at 192.168.106.1
"problem server" at…

Juha Laiho
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Fast ARP scan in address-less DAD (Duplicate Address Discovery) mode
I am developing system for detecting network actual state. One part is to get all IPs and their respective MAC addresses. Right now I am using arping in DAD (Duplicate Address Discovery) mode. I send arping for every possible IP in the ranges that…

Radek Hladík
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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: 1000baseT/Full
…

grs
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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 WAN interface. Does anyone know if this is…

IsaacB
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