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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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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143 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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368 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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205 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 ...
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1answer
353 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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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
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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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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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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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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
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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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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 ...
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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
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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
679 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 ...
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1answer
95 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
490 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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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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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
722 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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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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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 ...
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1answer
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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 ...
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260 views

Keepalived, Junos, and ARP caching

I'm trying to configure an active-passive stunnel setup, with the aid of Keepalived, for a public IP address at our company datacenter. I would like to know if a router or switch reconfiguration is ...
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1answer
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Permanant ARP entries become Unresolved

We have a solution where a number of Solaris servers are in a private VLAN and no arp proxies exist in this VLAN, so to reach neighboring servers we must add static arp entries. Each other server in ...
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ARP/Mac address table

What is the difference between a mac address table and an arp table? Is it correct to say only one arp cache is kept for each switch which self learns to forward information to another host, and every ...
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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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1answer
621 views

Broadcom NetXtreme II GigE Teaming Does Not Use Unique MAC, Causing Collisions

I currently have a new Dell server on my local (inside) network that I have setup to use three of the four nics to create a team. Examples below. NIC_1 - mac: 000000000001 - ip: n/a NIC_2 - mac: ...
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How to decrease linux box arp response?

I had known that I can not stop arp flood from others, so I wonder to know how can I decrease the response times per second, so that my cpu wont cost too much for arp flood, any tips?
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arp packet received larger than packet sent, why?

I'm trying to debug a networking issue. During this process, I've noticed that when I try to do an arping, the received arp packets are larger than sent arp packets, as outputted by tcpdump. (Note ...
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1answer
929 views

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 ...
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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 ...
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Protection from ARP spoofing

I'm running Linux and I know my gateway will always be 192.168.1.254 with MAC address aa:aa:aa:aa:aa:aa. Is there any way I can instruct my machine to only ever use this MAC address for the gateway ...
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arp reply is not processed

My eth0 interface does not process a legitimate arp reply. When I try to ping a host, I see arp request and reply with tcpdump from the host I try to ping from, but ip neigh says that there is a ...
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1answer
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Can arping by IP but not MAC address

I have an interface that I can arping to by its IP, but not its MAC address: # arping -i eth2 10.10.0.153 ARPING 10.10.0.153 60 bytes from 02:68:b3:29:da:98 (10.10.0.153): index=0 time=81.062 usec 60 ...
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3answers
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arp who-has requests view vlan isolated different addresses (single NIC)

I have debian hosts which are connected through trunk port on 5 different vlans. But this host respond to arp "who-has" requests of all of their differents ip. I wish understand why ... Here the ...
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2answers
683 views

Windows 7 Requires ARP for UDP?

Seems like my Windows 7 box (with 2 NICs if that's relevant) requires an ARP response before it sends packets to a certain IP address. The specific context I'm in is running a TFTP server (TFTPD32). ...
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639 views

Cannot ping any machine on local network (embedded linux device)

I have an embedded linux installation (custom built using buildroot, uClibc and busybox) and I am unable to ping any machine on my local network. My /etc/network/interfaces file is as follows auto lo ...
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Multiple VLANs - how Linux / Debian process packets

I can't find answer about how linux processes incoming packets from different VLANs, that do not belong to a subnet assigned to a VLAN. Imagine this situation. On Linux machine with the following ...
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1answer
485 views

Pinging between hosts through Layer2 tunnel fails

I have some serious problems with my newly setup network with a Layer 2 VPN tunnel. I draw a little diagram to show the simple version of the setup: The green lines are through the VPN, the blue ...
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1answer
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Cisco ARP table: determine directly connected devices

I have a Cisco switch and a big list of servers on the network. I need to determine what servers are connected directly to that switch. Will searching for the MAC address of each server in the ...
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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 Entries: 1 Skipped: 0 Found: 9 $ sudo arp -d 10.10.7.30 $ sudo arp -avn ? (10.10.7.30) at <incomplete> [ether] on eth0 I ...
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1answer
481 views

openvpn connects but does not work until server pings client

I'm trying to configure a connection using openvpn from a windows 7 client machine to a linux host. I'm using openvpn in the traditional routed mode using tap devices, and the configuration I'm using ...
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1answer
708 views

Switch CAM table and ARP messages

When the switch CAM table is empty and it receives an ARP message, does it add to the CAM table the source MAC address ? In Packet Tracer I saw that it does add it, but I read in some book that the ...
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What network traffic when ethernet plugged in [closed]

So in a general sense (e.g. not windows, linux specific) what network traffic is generated when I first boot up/plug in a network cable. Basically: Detect DHCP server Pull an IP Address from DHCP ...
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stop arp poisoning on a 5448 powerconnect switch

We have to disable arp poisoning on our dell 5448 switch. Right now it has all our production machines running on it and I'm not a networking guy at all so I don't want to run a command that will ...
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Dynamic ARP Entries turning into Static ARP entries

I recently acquired a client that has a strange ARP caching issue on one of thier servers. I have a server that will eventually start turning it's dynamic ARP entries into static ARP entries. This ...
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What is the meaning of the QUEUE in arptables

I use the nfqueue target of iptables in order to get packet to the nfqueue and do some business rules on them. iptables -A INPUT -p tcp -j NFQUEUE --queue-num 0 I need to do the same on arp reply ...
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Arp request is not resolved

On my machine, I have assigned ip addresses for two interfaces which are connected through a cable. They are connected with 10G ports. When i tried to ping the two addresses, ping was not working. ...
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Server Core DNS Server in VSphere doesn't respond to ping and needs continuous arp clean

I have a VSphere installation hosting two Windows Server 2008 R2 installations. One of them is a complete install that serves as a DHCP server and that I use for administration. The other install is a ...