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

2
votes
1answer
597 views

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 ...
2
votes
3answers
2k views

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 ...
1
vote
1answer
521 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: ...
1
vote
1answer
129 views

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?
2
votes
2answers
602 views

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 ...
4
votes
1answer
555 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 ...
12
votes
2answers
3k views

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 ...
1
vote
2answers
735 views

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 ...
1
vote
0answers
776 views

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 ...
1
vote
1answer
72 views

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 ...
2
votes
3answers
1k views

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 ...
3
votes
2answers
572 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). ...
1
vote
0answers
527 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 ...
0
votes
1answer
264 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 ...
1
vote
1answer
348 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 ...
2
votes
1answer
883 views

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 ...
4
votes
1answer
3k views

arp --detete is not deleting an entry; merely marks entry as “incomplete”

I run arp --delete and it leaves the entry but it's simply marked as incomplete. I expected --delete to entirely remove the entry. Does anyone understand what is occurring here? $ sudo arp -avn ? ...
1
vote
1answer
351 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 ...
0
votes
1answer
470 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 ...
-1
votes
1answer
54 views

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 ...
1
vote
0answers
255 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 ...
5
votes
0answers
634 views

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 ...
1
vote
0answers
127 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
936 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 ...
7
votes
1answer
5k views

How do I poll the ARP table with an SNMP OID?

When you need to poll the ARP table of a device, conventional wisdom is to use ipNetToMediaPhysAddress or atPhysAddress; however, both of these OIDs are deprecated according to Cisco's documentation. ...
5
votes
1answer
139 views

Sender Information Not Cached on the Receiver During an ARP Request

I'm currently trying to get my head around more advanced networking concepts. The way I am doing this is by going on one of the servers I look after as a sysadmin and running network captures to see ...
0
votes
1answer
476 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 ...
1
vote
1answer
443 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 ...
6
votes
1answer
887 views

Random and Selective ARP blindness in VMWare ESXi 4.1

We have multiple VMWare ESX servers spread out amongst our company, doing various tasks. One particular ESXi host is exhibiting very peculiar behavior. We detect it when our monitoring system ...
2
votes
1answer
1k views

Windows server sending constant ARP requests to offline devices

We have a Windows 2003r2 server which is sending intermittent ARP requests to several devices which are no longer on the network. The result of this is disruption to a PLC which is running over ...
9
votes
4answers
1k views

Network throughput issue (ARP-related)

The small college where I work is having some very strange network issues. I'm looking for any advice or ideas here. We were fine over the summer, but the trouble began few days after students ...
0
votes
1answer
477 views

Solaris Slow ARP Failure Unreachable Host

We have been experiencing slow timeouts for unreachable hosts is extremely slow. Recent testing in our lab shows it may be a delay reporting negative ARP lookups. Dumping traffic during attempts to ...
1
vote
2answers
219 views

Find IP address from a MAC address

Is there anyway to find the IP address of a MAC address using a command? I was thinking something like arping might work but can't seem to find much information on it.
2
votes
1answer
1k views

Failure to obtain IP with ARP over Wi-Fi with personal Wi-Fi router in client mode

I'm trying to connect a Samsung TV to the Internet using a TL-MR3020 personal wireless router in client mode. The TV fails to connect to the network. It sees the ethernet cable connected though. ...
4
votes
2answers
850 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 ...
1
vote
1answer
236 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 ...
0
votes
2answers
5k 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 ...
2
votes
2answers
469 views

pfSense 1.2.3 can't talk ARP beyond a switch two hops away

I have the following devices on vlan93 on my network: pfsense (192.168.93.1) core-sw1 (192.168.93.2) edge-sw1 (192.168.93.3) pf-switch (192.168.93.100) devices (192.168.93.120) Physical ...
6
votes
6answers
7k views

Cluster failover and strange gratuitous arp behavior

I am experiencing a strange Windows 2008R2 cluster related issue that is bothering me. I feel that I have come close as to what the issue is, but still don't fully understand what is happening. I ...
1
vote
0answers
336 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 ...
4
votes
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 ...
0
votes
1answer
844 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 ...
5
votes
2answers
355 views

Ubuntu 12 crashed and took down network

We recently set up a new Ubuntu 12.04LTS server on our network. It's not fully configured so it's not doing much beyond sshd and a default apache2 install. But this evening it appears to have ...
2
votes
2answers
316 views

Will a host accept any ARP response it gets and updates its cache

I am trying to understand ARP and ARP cache poisoning. Will a host updates its cache if it gets an ARP response even if it didnt send a request? If yes, is there any particular reason it is designed ...
-1
votes
2answers
315 views

Activate Passive Arp learning

I want to enable my linux-kernel to passively listen (learn) the arp request broadcasted in the lan segment (arp request in the network not destined for me). Is there any configuration available?
3
votes
1answer
1k views

pfsense single MAC is listed with several IP's in ARP table

I have this problem: arp table filling up But I am quite sure that I cannot blame Kaspersky. Scenarie: a user plugs his computer in. He waits and waits but are getting no IP by DHCP. Then he is ...
2
votes
2answers
283 views

Why computer scanning network?

I have found out through Wireshark that a computer in my subnet scanning network ( sending ARPs for every IP-address in my subnet. Even if there no computers with such address). It repeats ...
2
votes
4answers
1k views

Extremely high arp fllooding from the router

My subnet is 10.162.0.0/16. We have a router with a couple of interfaces. Gateway for my subnet is 10.162.0.1. The router is situated in another building and I haven't direct access to it. Line from ...