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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network level of veth doesn't respond to arp

I decided to play with veth : create a veth pair and send a ping from one end to another. $ ip link add type veth $ ip addr add 192.168.99.1 dev veth4 $ ip addr add 192.168.99.2 dev veth5 $ ip link ...
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3answers
772 views

Switch behavior on unicast packets when the destination is unknown

Please let me start by saying I am no network expert, I am a programmer who does a fair amount of L3/4 programming. My question is that when a switch receives a packet with a destination MAC that is ...
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4answers
109 views

Find out IP of connected interface?

Suppose I connect two machines directly together with an ethernet cable. I know nothing about machine2's configuration - I only have access to machine1. What can I do on machine1 to determine ...
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2answers
895 views

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 ...
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1answer
85 views

Can Windows Populate Network List in an MPLS?

With an MPLS of one host and one remote, when I go to Windows Explorer and bring up "Network", is the list supposed to be populated with the devices on both subnets? If not, can it be made to do so? ...
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1answer
2k views

brctl bridge forwarding packets to promiscuous interfaces

I have two promiscuous sniffing interfaces on my linux box: eth0 is connected to an external vlan bridge eth1 is connected to an internal vlan bridge with eth0 I can sniff all traffic on my ...
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150 views

Duplicate entries in switch ARP table

A server is showing twice or more on my L2 switch ARP table Same IP address, mac address, and ethernet port. What could be causing this? Thanks
3
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1answer
710 views

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 ...
0
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1answer
80 views

what would happen when macchanger to gateway mac address? [closed]

I thought arpspoof GATEWAY_IP -t VICTIM_IP can be prevented by add a static arp entry on victim side, i.e. arp -s GATEWAY_IP GATEWAY_MAC I read ...
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2answers
174 views

Is Windows Server 2008 R2 arp cache per user or per machine?

When running arp -a in a Windows Server 2008 R2 prompt, will the returned entries cover connections from all users logged on to the machine or only the current?
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1answer
236 views

How to convert proxy ARP setup to IPv6?

My company has a router/firewall deployed with the "common" Proxy ARP setup: it sits between some servers and the ISP gateway, and intercepts all the packets with proxy arp, so that it can apply both ...
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201 views

Ubuntu 12.04 reply ARP request delay 10+ seconds

I'm running Ubuntu 12.04 in VirtualBox, my server program is running in it, its IP is 192.168.1.105. My client is running at 192.168.1.107. But the client alway took 10+ seconds to send a package to ...
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1answer
2k views

Networking ARP table in windows cmd

I am reading the book practical packet analysis and I have just learned the fundamentals of the ARP protocol. They also added something about the arp -a cmd command. I'm curious about some of the ...
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2answers
604 views

Windows Domain controller ARPing for 169.254.0.0/16 addresses

I've been doing some sniffing on my company's network to try to clean up some of traffic and have noticed that one of our Server 2008 Domain Controllers is sending out ARP's every second or two to ...
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2answers
2k views

Physical switch not learning MAC address of virtual machines

I have a virtual environment running vSphere 5.1. I have two ESXis with a vDS between them. There is, for the purposes of the discussion, just one portgroup on that vDS configured to use a VLAN. The ...
0
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1answer
279 views

arpd does not send ARP requests

Sometimes a botnet (or whatever) tries to port scan pretty much all IPs in the internal network (two /21 subnets) in one second. As a result the router sends out a lot of ARP requests and some slower ...
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1answer
127 views

iptables arp compare and execute

EXAMPLE: iptables :internet - [0:0] -A internet -m mac --mac-source 48:5D:60:FC:29:B0 -j RETURN COMMIT [root@localhost:~ ] $ arp Address HWtype HWaddress Flags Mask ...
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1answer
72 views

Understanding ARP traces during OS load

Consider the following ARP packets captured while a unix machine was booting. From the packets I understand that this machine whose MAC address is 00:22:22:22:22:22 is requesting information about ...
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0answers
279 views

Keepalived failover not working for Static NAT target behind Cisco ASA

I've got a Cisco ASA[0] with a pair of Linux boxes in the DMZ running Keepalived and HAproxy acting as a load-balancing failover pair for another pair of Windows servers, also in the DMZ. I'm ...
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1answer
83 views

Move IP from one server to another without disruption

I have an internal DNS server running on a VM. I've rebuilt the server from scratch in a new VM, and I want to cut over from the old to the new at some point. In order to do this, I'll need to take ...
2
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0answers
169 views

I am not able to connect to my server from my leased line internet connection

I am having some troubles connecting to my Fedora server from my static IP ISP connection. Usually I can ping that server with no problems. But other times it just gives me timeout responses. When ...
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1answer
2k views

ARP response is not present on the other port of linux bridge based on ubuntu 13.10

I recently build linux based bridge for packet monitoring purpose, but there is BIG problem. the environment is, overall env. target of monitoring is VMs on vSphere. two vSwitches are configured ...
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2answers
2k views

Multiple NIC arp issue

I'm troubleshooting an issue on Centos 6.4. I have a few systems setting up for greenplum. Each one has two "interconnect" interfaces connecting to an isolated subnet. It is like a cluster ...
6
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1answer
2k views

Linux arp cache timeout values

I'm trying to configure sane values for the Linux kernel arp cache timeout, but I can't find a detailed explanation as to how they work anywhere. Even the kernel.org documentation doesn't give a good ...
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5answers
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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 ...
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0answers
182 views

Solaris 10 invalid ARP requests from 0.0.0.0? Link up/down every hour or 2

The guys at the data center where I'm hosting a server running Solaris 10 are telling me that my server is making a lot of invalid arp requests. This is an example of a portion of what was sent to me ...
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2answers
230 views

How to capture arp table when using network bridging?

I have a computer with 2 NICS that are bridged and I need a means of distinguishing between machines connected to eth0 from machines connected to eth1. I was hoping to use something like the "arp -a" ...
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2answers
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Can a computer route IP trafic between two LAN if it is not configured as gateway? [closed]

Having two LAN, each one have its own gateway, DHCP and internet connexion LAN 1 - IPs: 192.168.0.0-255, Mask: 255.255.254.0, Gateway: 192.168.0.1 LAN 2 - IPs: 192.168.1.1-255, Mask: 255.255.254.0, ...
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1answer
87 views

Host not showing in ARP even after broadcast

serverfault community. What I would like: to determine the current IP of a host (a networked camera to be specific) What I have: its MAC, its previously documented hostname and IP What I have ...
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1answer
224 views

How to discover devices other subnet [closed]

Printers like some thermal I have tried Bixolon and samsung laser printer ,even mikrotik router have a tool where they discover the device via its mac address.No matter what the ip is. And they ...
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0answers
130 views

ARP Tables on Windows vs Linux

I noticed on Windows Server 2008, Windows Server 2008 R2, and Windows 7 that IP multicast groups joined by a computer are recorded in the ARP table as static addresses automatically. However, the same ...
3
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1answer
261 views

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 ...
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2answers
302 views

Excessive ARP request with no reply

I had been monitoring our LAN setting due to slow bandwidth. In the wireshark, I am seeing an ARP request that is never resolve to a MAC address from the same IP address. I did a NMAP scan, the ...
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2answers
675 views

Why do all computers on my network have the same MAC address?

I'm on a LAN provided by an ISP. My computer has its IP address, Subnet Mask, Default Gateway, DNS Servers(using DHCP). I just wanted to see the MAC addresses of all the computers on my LAN. After ...
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1answer
2k views

How to resolve an IP address to hostname

This is my first time trying to work with an ARP so I'm slightly lost as to what I'm missing. I'm probably going down the wrong track, so lemme know if I'm completely and utterly off. What I'm trying ...
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1answer
602 views

Cannot ping gateway

I replaced my aging fileserver with a new server running ESXi 5.1 and migrated my fileserver in a virtual machine running on it. Now I have the following problem with this VM: I'm getting the ...
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2answers
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Multiple NICs with IPs from same network at Linux host respond to a single MAC

CentOS host is armed with multiple NICs. All NICs are bound to the same subnetwork (let it be 10.0.0.0/24). Their IP configuration is provided with DHCP server (as reservations). While trying to get ...
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2answers
729 views

ARP Command doesn't display all devices

I have a machine on my network that needs to create a list of all mac addresses connected to the network. This is running OSX when I run the arp command it doesn't always display everything connected ...
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871 views

VMWare ESXi 5.0 Networking Issue

I have an issue with 2 new ESXi hosts. OS - ESXi5.0 Custom Dell ISO patched up to Build 1024429 DELL R820 with 1G network 2 ports from integrated MB NIC(Intel) connected to 2 juniper switches, one is ...
2
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0answers
67 views

ipwatchd detects non-existing conflict?

Ipwatchd is telling me about a conflict that I just do not understand. As far as I can tell, there is no conflict. Am I reading the message wrong? It's a Xen machine with the following network ...
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2answers
1k views

Broadcom Advanced Control Suite 4 on a PowerConnect 2848 making router (ASA5505) throw ARP errors when TEAMING (different MAC addresses from same IP)

For some reason the Broadcom Advanced Control Suite 4 seems to be a little buggy OR I have not configured something correctly. I have 4 Gb NICs and I team 3 of them to make a virtual adaptor... ...
4
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1answer
517 views

Cannot ping B from A until B pings A

I have a server cluster all connected on a local network(all physical machines, not virtual). When trying to ping from Server A to B, I get a Desitination Host Unreachable. I can ping from B to A no ...
1
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1answer
85 views

Can you SNMP poll the ARP table on Cisco ACE?

I'm trying to get a MAC <=> IP mapping from a Cisco ACE. Unfortunately according to this table, while it supports IP-MIB the ipNetToMediaTable and ipNetToPhysicalTable subtrees are not supported. ...
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2answers
343 views

Can a duplicate computer name be known before attempting to join the domain?

Techs in the field are deploying windows 7 pcs onto a domain. They complete one entry screen, which should give them a unique computer name. However, they are human and end up giving the pcs the ...
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616 views

Trouble directing traffic to Honeyd virtual hosts

I am trying to set up an experiment to observe some network behavior and as part of that experiment I am setting up a closed LAN that has virtual hosts created by Honeyd. I have honeyd running one ...
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3answers
5k views

Wireshark running on a server seeing lots of `ARP who has` with different tells

We're seeing some suspicious network activity, and when I was trying to see if it was one particular server of ours I ran a Wireshark trace. I noted a lot of ARP packets asking who has x.x.x.x, but ...
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1answer
554 views

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 ...
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0answers
82 views

Can ARP with IP aliases on Windows be made to behave like on Unix?

On FreeBSD, when I have one interface with two IPs: ifconfig nic0 192.168.0.1 netmask 255.255.255.0 ifconfig nic0 alias 192.168.0.2 netmask 255.255.255.255 If I ping the alias, if the host I'm ...
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1answer
267 views

automatic scanning for duplicate IPs - program needed [closed]

we need a solution to automatically scan for IP conflicts our subnet (192.168.0.x / 255.255.255.0) multiple times a day, and alert us if one is found. At the moment I use the arping program under ...
2
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1answer
2k views

Which are the possible reasons for an arp request that is not being solved/answered?

This weekend I was testing a new data link connection from a service provider, and I went through some address resolutions problems. I tested reachability to hosts at the far end using a laptop on my ...