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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Is it the normal behavior of arp requests?

Sometimes I dive into my network and often I see: tcpdump -n arp 17:59:15.754508 ARP, Request who-has 192.168.1.65 tell 192.168.1.212, length 28 17:59:16.754401 ARP, Request who-has 192.168.1.65 ...
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How to reverse arp using nping for Windows

I would like to send a reverse ARP to resolve an IP address given a MAC address using nping for Windows. The documentation is not clear on how this should work and I'm unable to find any examples ...
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4answers
59 views

Fault tolerance by using two IP with two interfaces

I would like to have a fault-tolerant setup for http requests. For brevity, let's assume we have a very simple Web-service and there is no difference which server responses. So I will have the ...
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1answer
54 views

First Reply on Ping is Unreachable the rest is okay [closed]

please check this weird ping i'm having What may have caused this problem
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95 views

KVM Windows guest macvtap host device bridge no access to network but DHCP works

KVM on CentOS 7, guest OS windows 7 x64, I need the guest to have direct access to network and let my network infrastructure to handle IP addressing. In virt-manager, I set NIC to: source device => ...
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30 views

arp poisoning and mitm protection [closed]

I'm trying to understand mitm by arp poisoning. To do so I'm practicing on the network I manage: attacker : IPA victim : IPC gateway : IPG I use nighthawk, and kali linux (via virtual box). I can ...
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1answer
62 views

How to troubleshoot internet unreachable periodically through firewall

Periodically the internet is unreachable on my network, sometimes for 30+ minutes. After testing a direct connection to our modem, I realized this was not a problem with our ISP but the network ...
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2answers
201 views

Linux is sending ARP requests to hosts in other subnets?

Setup Host B <--> Router <--> Host A Host A: IP = 192.168.1.10, Net = 192.168.1.0/24, VLAN = 1, Default GW = 192.168.1.1 (Router) Host B: IP = 192.168.2.10, Net = 192.168.2.0/24, VLAN ...
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92 views

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 ...
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68 views

linux not replying to an arp request

I am running linux 3.14 on a system with 2 interfaces. on the first interface, i can access our local network. on the second interface, arp packets come in but linux doesn't send out reply. is it ...
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2answers
251 views

How is a TCP request routed from a virtual machine to an outside resource and back again?

Scenario: Computer A has a local ip of 192.168.1.100, which is running a VM inside of it. The VM now makes a tcp request to an external IP address (74.125.225.98). Could someone explain how the ...
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1answer
162 views

Cisco ASA 5510 needs “clear arp <Interface>” periodically to reach a single host

ASA 9.0(3) The symptom is that I can ping from the ASA to any other host in that interface's subnet, save one particular host (that host can ping the interface on the ASA however). If I do "clear arp ...
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1answer
52 views

iptables: service per physical interface

I have a vm on which I'm trying to configure (unsuccessfully) one service per physical device - i.e. ssh open only on eth0, http only on eth1 and ftp only on eth2. This has to happen regardless on the ...
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1answer
194 views

How does Bind IP to MAC work? [closed]

A client is connected to the network with a DHCP server, but also has a Bind IP to MAC entry in the router. What is the sequence of steps that determine the final client IP configuration given that ...
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2answers
83 views

Why am I not getting an ARP reply with this request?

Using pcap_sendpacket in C, I'm manually sending the following packet on wlan0 (I've left out some fields, but I think they are correct): (Ethernet layer) eth src: <wlan0 MAC address> eth ...
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30 views

How to meet the arp table and the network toology with wireshark

I'm wondering if is possible meet(see) the arp table in a network traffic with wireshark or find some way to build manually the arp table, and how to see the router and swiches of topology( for ...
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117 views

Broadcom NICs, Cisco ASA and ARP request collisions

First of all I am sorry for my english mistakes. Help me please to solve the problem with ARP request collision incidents. I have IBM BladeCenter E chasis with blade servers are installed in this ...
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0answers
58 views

FreeBSD jail loses network connectivity after some time

I have a Jail on a FreeBSD 9.2 installation on my office network, which I use to run some cron jobs that upload and download stuff from external servers. The cron jobs are configured on the main ...
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84 views

Pinging two virtual interfaces(IP aliasing) not working

I have two VMs. I have created a virtual interface on each of the VMs. On VM1: eth0 Link encap:Ethernet HWaddr 06:98:82:00:00:39 inet addr:10.129.34.76 Bcast:10.129.255.255 ...
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2answers
195 views

External ip address being treated as local (ARP asking for external IP's address)

I am using a virtual machine with OpenWRT for routing, on a Linux machine (Slackware). I am trying to configure a host only interface (eth0) as the wan interface. eth1 is Ethernet attached as a bridge ...
0
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1answer
85 views

How can I tell what's happening to my packets?

I'm trying to bring up a little box on my network. I just reflashed the firmware and it's supposed to come up as 192.168.1.1 by default. My router is a DSL modem at 192.168.0.1; it usually uses a ...
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265 views

VMWare use of Gratuitous ARP REPLY

I have an ESXi cluster that hosts several Windows Server VMs and around 30 Windows workstation VMs. Packet captures show a high number of ARP replies of the form: -sender_ip: VM IP -sender_mac: VM ...
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47 views

How to fix stalled connection on large download

I have a cisco 1921 router performing routing and NAT function. Cisco 3750 is performing layer 3 core switching duties. Users are complaining about large file transfers being stalled (not dropped) ...
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2answers
130 views

Windows 8 is not always selecting correct network card for my outgoing transmissions

The company I work for builds and sells industrial machines. One of our products is a machine which is controlled by a PC running Windows. This particular machine uses a networked device with ...
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92 views

X520-DA2 10GbE PCIe NIC on Ubuntu 12.04 doesn't respond correct ARP information for a traffic tester

I'm trying to configure stand-alone test network to examine a server that has two 10GbE ports PCIe NIC. But I couldn't get any ARP responses of those 10GbE ports. To execute my test, it's necessary to ...
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1answer
149 views

Directed ARP requests do not arrive at bridge interface

I'm baffled by the following weird bridge/arp behavior under Linux. It somehow seems to filter directed ARP requests, whereas it should forward them to the other end of the bridge. To test, I run the ...
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31 views

SYN-ACK with identical MACs

What could cause a CentOS machine to respond with SYN-ACK packet having both source and destination MACs set to the address of the NIC from which the packet is being sent?
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1answer
173 views

Group Policy for Time Sync = ARP Flood?

I have a Windows Server 2008 R2 domain controller and a bunch of workstations of various versions of Windows - XP SP3, Vista, 7, 8.1. Time sync wasn't working correctly on a few PCs so I followed the ...
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52 views

Strange network issue when moving EC2 elastic IP

Recently we had an issue with a Windows 2012 EC2 server, which meant that we had to move across to another instance. We duplicated the instance, ran some tests and moved over the elastic IP. Should ...
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1answer
611 views

arp problems with transparent bridge on linux

I've been trying to secure my virtual machines on my esx server by putting them behind a transparent bridge with 2 interfaces, one in front, one at the back. My intention is to put all the firewall ...
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2answers
138 views

Must an ARP broadcast query packet contain the target node's MAC address [closed]

So far as I know, Address Resolution Protocol (ARP), translates the IP address of a computer on a local network to an equivalent layer 2 address (MAC address), such as sending a packet from machine A ...
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1answer
315 views

Determine the hostnames of IP conflict

I have a network with several hundred machines on it. I have a machine that gives intermittent connectivity issues, reported via vSphere web client. This troublesome machine has the hostname ...
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190 views

Linux (Ubuntu 12.04) sending ARP requests over single interface

I have a system with custom hardware hooked up to 2 different ethernet ports on the same system. The interfaces are configured on the same subnet because the hardware (FPGA-based) has a hardcoded IP ...
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124 views

localhost answering wrong ip

No idea how/why, but here's what I'm seeing. Consider 3 CentOS 5.10 boxes: Host A [10.1.2.7] Host B [10.1.2.8] Host C [10.1.2.9] All of a sudden we're getting strange behavior from Host X, ...
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3answers
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Prevent Linux server host from using ARP

If I know all client will connect to the sever with the same MAC address and to the same interface, is it possible to prevent from server host to send ARP request for each new client IP it gets a ...
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1answer
137 views

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 ...
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1answer
343 views

“Destination Host Unreachable” and ARP returns no addresses over LAN

I am currently trying to setup LAN over two machines with a network mask of 255.255.255.0 however I am receiving the following message when trying to communicate between them both; [root@alpha ~]# ...
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1answer
205 views

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
517 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
104 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
785 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
73 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
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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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121 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
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1answer
581 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 ...
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1answer
77 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
122 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
186 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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182 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
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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 ...