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.

learn more… | top users | synonyms

1
vote
0answers
498 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 ...
1
vote
1answer
332 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 ...
1
vote
1answer
339 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 ...
1
vote
0answers
234 views

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 ...
1
vote
0answers
124 views

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 ...
1
vote
0answers
890 views

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. ...
1
vote
0answers
61 views

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 ...
1
vote
1answer
430 views

Update mysql database with arpwatch textfile database

I'm looking to keep arpwatch entries in a mysql database to crossreference with other information I'm storing based on mac addresses. I've manually imported the arpwatch database into my mysql ...
1
vote
1answer
222 views

Proxy arp and 1:1 NAT

I have a Linux router with 2 NICs doing masquerade from network 192.168.0.0/24 to an ADSL router. users <----> NIC A [router] NIC B <----> INTERNET Now I'm experimenting with proxy arp ...
1
vote
0answers
330 views

virtualbox bridged adaptor works only guest->host but not host->guest

I have virtualbox 4.1 on a ubuntu 12.04 host. On my host I have a virtual interface eth0:1 configurend as 10.0.1.1. I have a few virtual machines using bridged adapters, configured in the 10.0.1.0 net ...
1
vote
2answers
1k views

Routing to other subnets results in wrong ARP requests

I would like to manually set up routing to subnet 95.168.0.0/16 through IP which is an alias: 94.23.94.161. IP alias is set up like that: /sbin/ifconfig eth0:0 94.23.94.161 netmask 255.255.255.255 ...
1
vote
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 ...
1
vote
0answers
318 views

Windows Server 2003 DC sends Gratuitous ARP requests with wrong IP

Hello and excuse me for my English please. ;-) Two server seems to be involved with this problem. Our DC (domain controller, 2003) an the VMware VC-Server (2008 R2). After capture "some" network ...
1
vote
1answer
644 views

arp requests are sent continuously and my linux machine disconnected to the world [closed]

I have the following problem and really need your help I'm implementing a small server to receive request from client on port 18999(just sample) using TCP socket. When I tested my server by using a ...
1
vote
2answers
412 views

Is there a way to trace what's sending gratuitous arps?

We have a box that's just started acting up and we're not really sure why. It has IP address (dummy examples) 199.199.199.1 on eth0, 127.0.0.2 on eth1, and 199.199.199.2 on eth1:0. Recently, for some ...
1
vote
1answer
80 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 ...
0
votes
2answers
152 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 ...
0
votes
1answer
443 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 ...
0
votes
6answers
3k views

Network routing issues on Linux

I was hoping someone out there would be able to look at this and let me know what I have missed. I have 4 machines and for some reason, only 1 of them can talk to the other 3 via their private IP ...
0
votes
5answers
743 views

Computers on one subnet can't connect to the internet

I have an issue with my student computers - they can't connect to the internet. Here's the weird part: I open a command prompt and ping our gateway server, and suddenly everything is fine (at least ...
0
votes
2answers
12k views

No answer on arp requests?

I have a problem where my Layer 3 Dell PowerConnect 6248 Switch (main switch) will sometimes (that means sometimes it works, sometimes it won't) not get an arp response from a device behind Dell ...
0
votes
2answers
288 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 ...
0
votes
2answers
2k views

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 ...
0
votes
3answers
1k views

ARP broadcast and router performance

My employer subscribes to a fiber based leased Internet from a publicly owned incumbent ISP. The ISP admin says that he cannot give a subnet bigger than /30 because he fears that the ISP edge router ...
0
votes
2answers
173 views

Is a low-bandwidth arp-scan potentially disruptive to persistent TCP connections on the same LAN?

First a little background: On the (isolated) /16 LAN in question, we have several devices that keep several persistent TCP connections open between them. The program at each end of these TCP ...
0
votes
1answer
138 views

arp result interpretation

So what does the command arp -a do? I've been told it displayed the MAC addresses of all network cards on the computer, but when I ran it, it displayed three MACs for three IPs (192.168.41.1, .6, and ...
0
votes
2answers
96 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 ...
0
votes
1answer
78 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 ...
0
votes
1answer
405 views

ARP Connectivity on cisco small LAN

I feel so lame to have this doubt, so there is the question : Why do I not have connectivity ? The case is simple, I have configured the topology and have connectivity between each PC and respective ...
0
votes
1answer
580 views

Router is continually broadcasting the same ARP request, with the exact contents

I hope the question is clear and that this is correct place to post the question. My router is broadcasting the same ARP frame over and over (once every second). It's probably not a big deal, but I ...
0
votes
1answer
2k views

Why is a ping response being sent to the wrong gateway?

In a previous question, I was trying to determine why my OpenVPN clients could not ping the server LAN, even though the server LAN could ping the clients. Having investigated this further, I ...
0
votes
2answers
204 views

ARP requests, etc.

I'm trying to run arp spoofing on a network. I've been working on this for about a week, and all the information I find is dated year 2000-2001. My issue is, after testing a script that uses ...
0
votes
1answer
88 views

What would cause a Windows 2008 server to switch destination MACs in the middle of a TCP session?

My Windows 2008 server started a TCP session talking to one destination mac address, but in the middle of the TCP session started sending packets to another destination mac address and then eventually ...
0
votes
1answer
577 views

CISCO: ARP Poisoning Countermeasures

How can I prevent the Cisco Catalysts 2950/2960/3550/3750 from being vulnerable to ARP Poisoning? Can this be avoided with the ARP INSPECTION? Thanks
0
votes
2answers
33 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 ...
0
votes
4answers
64 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 ...
0
votes
1answer
53 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 ...
0
votes
2answers
152 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 ...
0
votes
1answer
186 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 ...
0
votes
1answer
79 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? ...
0
votes
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 ...
0
votes
1answer
536 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 ...
0
votes
1answer
262 views

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 ...
0
votes
1answer
464 views

arp across subnets which devices can be detected?

i have some devices connected in the same physical network (LAN) but in different subnets. I want to detect them all with the ARP from my computer. My Computer is also in the same physical network but ...
0
votes
2answers
4k views

arp -n responds with (incomplete) on the wrong subnet, can't remove it

context There are 2 servers: server1 - eth0 10.129.76.16 eth0.2 192.168.0.103 server2 - eth0 10.129.79.1 eth0.2 192.168.62.101 The 192.x.x.x addresses are connected to the ...
0
votes
1answer
817 views

One To One NAT, only works on WAN?

We are attempting to test a One To One NAT configuration on a Cisco RV180 router, Cisco SMB support says that this setup below would not work. (they seem to be right) I know it has something to do ...
0
votes
1answer
2k views

Linux storing arp cache entries using wrong interface

I'm trying to get two virtual machines (running CentOS) to talk to host (Ubuntu 10.04) using VDE and the outside network. So far I'm running into an ARP issue. On Host I have a physical eth0 and a ...
0
votes
1answer
1k views

Many ARP requests in TCP dump?

I have been experiencing very slow upload speeds on my cable network lately. I ran a tcpdump and found many ARP requests. I'm not sure what process they are coming from, but could this be related to ...
0
votes
2answers
316 views

postgres fallback to standby server, switching ip address, clear ARP cache

I'm using a hot standby server for my postgres database. I've assigned a virtual ip address to the server. In case of a failure I'm switching the virtual ip from the master to the hot standby server. ...
0
votes
3answers
459 views

Is this how ARP works? [closed]

A wants to send a datagram to B. A knows B's IP address. However B's MAC address is not in A's ARP table. So A broadcasts an ARP query packet to all machines on the LAN. B recognizes it's IP, so it ...