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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New server unreachable for a time after swapping IP address

I am migrating nearly 20 websites from a win 2003 server to a win 2012 server. Both are VMware VM's, on different boxes, but in the same server room, and attached to the same switch. The 2003 server ...
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1answer
9 views

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)
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2answers
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ARP reply vanishes from br0 to tap0 using OpenVPN in bridging mode

i have setup a linux box (on an esxi5) which acts as an openvpn server. the server is configured to use bridging for the clients, which essentially works, with one exception. if the client pings some ...
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2answers
27 views

arp table entry outside configured network

Can someone tell me why do I have arp table entry outside interface network? Server has 2 interfaces, both on the same network: eth0 10.10.34.146/22 eth1 10.10.33.188/22 ip route default via ...
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4answers
3k views

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, ...
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0answers
25 views

ARP/ICMP in a network environment with overlapping IP address

Currently I have lab network setup to mimic customer's network deployment. (According to the customer, they are using VRF over VLAN so that their customer can have overlapping network connecting to ...
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8answers
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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 ...
0
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1answer
21 views

Master and slave devices talking to each other through another device with two interfaces. All in the same network

I have three devices, one is a master which will talk with the slave and Device3 but it is only physically connected to the Device3. The slave will speak only with the master(also through the ...
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1answer
2k views

How to setup a static multicast ARP entry with Cisco SG300?

We're running a Microsoft NLB cluster in multicast mode as a loadbalancer. Using our old Cisco IOS switches we propagate access to the cluster to our branches using a static ARP entry in the core ...
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2answers
37 views

Is turning off ARP a common practice?

I'm just trying to diagnose a problem I and a colleague have had on two separate occasions to swap out an old router with a new one. Both starting from scratch, we've found that we can't seem to ...
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1answer
1k views

How are ARP reply collisions typically handled?

If a node receives multiple, conflicting ARP replies, what happens?
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0answers
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Polycom VOIP phone seems to mask the secondary device's MAC address from a Cisco switch

When I have a Polycom VOIP phone plugged into a Cisco switch and a laptop plugged into the Polycom phone I get the following. 1) The phone goes into the voice VLAN as expected. 2) The laptop goes ...
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20 views

Broadcast ARP weirdness

we a running a router on a custom Linux box. Kernel is 3.14.14. What happens is that when you arping the router in broadcast only mode is the router has a verey slow response time: # arping -b -c ...
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2answers
823 views

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 ...
3
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1answer
70 views

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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1answer
245 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 ...
0
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1answer
93 views

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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6answers
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Is it possible to match an internal IP address to a switch port?

I'm trying to find a computer that has a certain IP address on our internal network. I have identified the computer name from DNS, but in this case it does not help me. Just wondering if I can ...
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1answer
61 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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1answer
153 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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4answers
66 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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0answers
200 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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0answers
37 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
73 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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6answers
9k views

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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2answers
386 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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3answers
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Linux machine does not answer an ARP request

We have this situation: A router, which is an Ubuntu VM, has multiple VLAN interfaces on the same physical NIC. Those VLAN interfaces are dynamically configured and torn down and attached to networks ...
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0answers
111 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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0answers
83 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
261 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 ...
0
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1answer
55 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
300 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
102 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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0answers
32 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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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 ...
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0answers
145 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
63 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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0answers
103 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
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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 ...
0
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2answers
245 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
102 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 ...
4
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1answer
4k views

Why ARP request is unicast?

I have a wireshark capture that indicating a unicast ARP request from source to destination. As per my understanding ARP requests (including gratutious ARP) use broadcast. In what case the ...
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0answers
313 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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1answer
709 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 ...
2
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2answers
2k views

How can I configure permanent arp entries on Red Hat Enterprise Linux?

I'm configuring a Red Hat Linux server which will be sending UDP packets out but never receiving ARP responses. So a static ARP entry is required. The obvious way to do this is. arp -s 10.0.0.1 ...
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51 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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1answer
173 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 ...
0
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2answers
174 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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0answers
100 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 ...