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

3
votes
1answer
106 views

When wouldn't an ARP reply be generated?

Summary of the problem: a ping from client does not go to rpi1, its ARP call is not answerd at srv. host0and tap0 are bridged by br0. vpninand lan0 are two independent interfaces. All traffic ...
0
votes
1answer
31 views

ARP spoofing on switch across subnets

Consider a switch without any VLAN's defined with 2 subnets configured. Is it possible to ARP spoof from one subnet to another? According to Evans reply in What are the implications of having two ...
0
votes
0answers
7 views

libvirt bridge is not forwarding arp replys

I did set up an vm with libvirt but it gets only sometimes network connectivity. I could narrow the problem down to the bridge is not forwarding the arp replys from the vm. From within the VM I can ...
1
vote
1answer
26 views

FreeBSD bridge ARP replies not forwarded

I have a bridge between two networks using the same address space, and have very strange issues with ARP packets. Interface bridge0 has no IP address assigned, and has two members : em1 and em2. A ...
0
votes
0answers
12 views

Diagnosing the source of improper ARP requests on WAN side of Linux firewall/router

The kernel log on a Linux firewall/router I administer recently started filling with messages like these: net_ratelimit: 405 callbacks suppressed neighbour: arp_cache: neighbor table overflow! ...
0
votes
0answers
29 views

initial connections refused - connection warm up?

I've got two firewalled VMs connected to the same vLAN but I see RST/ACK responses on initial connection attempts in a while only to succeed on immediate following attempts, like some sort of cache ...
0
votes
1answer
45 views

iptable and ARP setup of linux router under a wifi network

My problem is the computer under the WiFi network cannot connect to the computer under a Linux hotspot which is connecting to the same WiFi. I am setting up a Linux hotspot under a WiFi network, ...
0
votes
2answers
39 views

esxi arp cache not showing VLAN neighbours

On my ESXi 5.5 host I have 3 VLAN's plus one management (non-VLAN) LAN. When I print the arp cache (as show below) I notice that only the management LAN addresses are show (192.168.1.x). How do I ...
0
votes
0answers
58 views

“No route to host” when i do a telnet in azure

I have two VM's in azure with different public IP's and whose private IP's are : 10.10.1.9 10.10.1.6 When i do a telnet with following command from the server 10.10.1.6, i get the a error: telnet ...
0
votes
2answers
55 views

Finding ip address from mac addess

I have router in bridge mode which is installed Openwrt and I want to find IP address of devices which are connected to the router. Since router is in bridge mode, I can not find IP from DHCP leases, ...
0
votes
1answer
63 views

TCP connection RST after FIN, ACK

I have a situation that would like to clarify with the experts here. I am no network expert so maybe it's normal, but i rather ask. We are trying to diagnose a problem between two servers, both are ...
0
votes
1answer
47 views

Xen Server interference on ARP requests

I have a strange behaviour on my network as my unix-like hosts seem to have problems to reach the gateway. Digging into the network traffic via tcpdump, I've seen that two different hosts answer to ...
0
votes
0answers
15 views

Firewall thinks ARP is being spoofed

My firewall log is filling with messages about a possible ARP spoofing attempt on my own LAN: 192.168.111.60 is a Synology RS815RP+ NAS on my LAN. 192.168.111.7 is a Lenovo EMC px4-300r NAS. Both ...
1
vote
0answers
50 views

Understanding arp request tcpdump

I noticed the below tcp dump when pinging a docker container B on bridge B from a docker container A on bridge A. Container A: 10.0.0.3 / 02:42:0a:00:00:03 Container B: 10.0.0.4 / 02:42:0a:...
0
votes
0answers
12 views

Frequent unicast ARP requests

Wireshark screen I would like to ask if it's considered to be a normal behavior of a router to issue this many (as shown in the screenshot) "refreshing" arp request? As I do not see, for instance, my ...
2
votes
1answer
72 views

Juniper EX3200 connected to Cisco 2900 series router - incomplete ARP entry

I'm tying to connect a Call Manager Express running on a Cisco 2900 series router to a Juniper EX3200 switch. I have both configured on VLAN 4, with both ports in access mode but when I connect the ...
0
votes
0answers
43 views

What is the difference between arp_ignore and arp_filter?

What is the exact difference between the arp_ignore flag and the arp_filter flag defined in syctl.conf in Linux? Both seems to serve the same purpose.
0
votes
1answer
34 views

Make Linux reply to certain ARP requsts

I’m trying to pull a certain routing stunt where I want my Linux server to respond to arp requests for 10.0.0.1 on eth0, although 10.0.0.1 is not the configured IP for eth0 (in which case the ...
2
votes
0answers
56 views

Ping problems with two interfaces, same subnet, direct connections to two separate hosts

I have a configuration of a client machine (Ubuntu 14.04.2 LTS) that directly connects to two server machines. The server machines--while on the same subnet--cannot route to each other. Packets must ...
4
votes
2answers
129 views

When do STALE arp entries become FAILED when never used?

root@openwrt:~# ip -s -s -4 neigh show dev lan 10.64.42.121 lladdr b8:20:00:00:00:00 used 6387/6341/6313 probes 1 STALE 10.64.42.157 lladdr b8:20:00:00:00:00 used 24/813/19 probes 1 STALE 10.64.42.12 ...
0
votes
1answer
71 views

iwconfig and arp commands report slightly different MAC addresses

I'm at a wifi hotspot where, when I look up the router's MAC address by two different methods, I get slightly different results: $ arp -a ? (10.128.128.128) at 00:18:0a:58:WX:YZ [ether] on wlan0 ? (...
0
votes
0answers
49 views

arpwatch to listen only to particular network

I deploy arpwatch is our network and it is working fine. But it is not doing exactly what i need. Here is what i need ... i want it to listen to one particular network ... for example on ethernet 0 it ...
0
votes
1answer
31 views

sudden increase in arp entries when i rlogin from one node to another node

when I r-login from my one host to another, I am observing sudden increase in arp entries from 80 to 900. and this is causing neighbour table overflow. can anyone suggest why this is happening?? ...
-1
votes
1answer
135 views

Default gateway and ARP confusion

I have the following configuration (I'd post a pic but not enough rep for more than 2): PC1 (10.0.2.10/24) and PC2 (10.0.2.137/29) are connected to a hub, which is connected to a router on interface ...
0
votes
0answers
55 views

ARP cache getting null mac over a bridge

I have an interface eno1 and a bridge br0 $ ifconfig br0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 inet 192.168.250.53 netmask 255.255.255.0 broadcast 192.168.250.255 ...
0
votes
1answer
121 views

First ping (to any destination) fails from switch but not from router

I've got a basic network setup, just doing NAT to a single public address to an internal /24 without any VLAN's or fancy routing. Both my router and switch are running Cisco IOS 12.x. My ...
-2
votes
3answers
59 views

Obtain MAC address of remote, unconfigured device?

I have a device that goes on the network. I need it's MAC address. There is no label on it. How do I do that? I have no access to the device itself. I can power it on and plug it in to a switch ...
0
votes
1answer
108 views

Cisco WAP321 dropping ARP packets

At my office we have 4 WAP321 connected directly to a Cisco 891f router. Randomly throughout the day, computers will lose access to the network. They will remain connected to the Wifi SSID, but can't ...
1
vote
0answers
29 views

ESX 6 arp fails in back 2 back link

we are having a strange problem with back 2 back connection between an ESX 6 and CentOS 7 machine. Hoping to find a solution on stackoverflow The story is below: - we are using a CentOS 7 directly ...
3
votes
0answers
67 views

ARP behavior in Linux

I have a L3 switch. Port 1 and port 2 of the switch are added to VLAN 30 and an IP address (30.0.0.1) is assigned to it. Port1 and port2 are connected to Host1 and Host2 respectively. Host 1 and ...
3
votes
0answers
95 views

Xen networking - dom0 receives ARP requests but no reachability

Both dom0 and domU are Debian 8. Dom0 network configuration is: auto xenbr0 iface xenbr0 inet manual bridge_ports eth1 bridge_stp off bridge_waitport 0 bridge_fd 0 auto xenbr0.4 ...
0
votes
1answer
92 views

Cisco IPv6 Proxy-arp like IPv4

Can I disable the proxy-arp in IPv6 in Cisco? I cannot find the "no ipv6 proxy-arp" command in my Cisco router. Please teach me how to do it. Thanks.
3
votes
0answers
227 views

Windows 10 arp cache getting stuck after failed attempts when target machines are offline

After upgrading our development team to Windows 10 from 7, we are experiencing an issue with the ARP cache where a machine has the correct IP-MAC mapping cached, but the type is invalid due to failed ...
0
votes
0answers
65 views

Cisco 2960X & IPDT

I am interested in finding the IP addresses assigned to devices attached to each interface on a Cisco 2960X switch. It seems like IPDT is exactly what I'm looking for. However it seems like the ...
1
vote
1answer
135 views

ARP Request Being Sent To Different Subnet From Ubuntu Linux

This question is very similar to this one: Linux is sending ARP requests to hosts in other subnets? Main problem - Ubuntu Linux server is sending ARP requests asking for a MAC address of a host on a ...
0
votes
0answers
47 views

Ubuntu - Destination Host Unreachable Through Router / ARP Requests

Very strange issues on an Ubuntu server running DNS. Here is the network setup. There are two class C network ranges. Let's say they are: 216.107.249.0/24 216.107.250.0/24 Server is assigned an ...
1
vote
0answers
71 views

ARP issuse in SUSE Linux

I am dealing with a very strange problem. I have a VM running SLES 11 SP4 in VMware Environment. The machine has two NIC. All of a sudden the second NIC stopped working. It's not even pinging the ...
1
vote
1answer
46 views

Not sending an ARP request to avoid IP conflict

I am working on Ubuntu. I am setting a static IPv4 for my wireless interface (ifconfig wlan0 192.168.1.2) and connecting to a Wireless Access point and pinging it. I don't see in the sniffer that ...
0
votes
0answers
179 views

http cookie contains datr not working (none packets is returned) wireshark

When I filter in wireshark: http.cookie contains datr none packets is returned, the list in null. What's I going wrong?
0
votes
1answer
126 views

How to make a simple network bridge in Vagrant?

I'm trying do set up the most basic network bridge demo in Vagrant. I have two machines in the same subnet, but on different LANs, and a bridge machine with two interfaces and a network bridge that ...
2
votes
1answer
71 views

Accessing a server with wrong IP out of segment range

I have run into a similar problem as in this question about a wrong IP in LAN. However, the standard addr alias trick on the NIC did not help. I have no direct access to the server console, I might ...
0
votes
0answers
173 views

(solved -> bug) forward arp packets as vlan tagged arp packets

How can i forward arp packets as vlan tagged arp packets? e.g. arp packet (no vlan tag) -> eth1 -> eth2.1 -> arp packet (with vlan tag) With the following setup, the outgoing arp packets (on eth2.1) ...
1
vote
0answers
33 views

Arp reply on behalf of another devices on Linux

There are devices on a network that don't support ARP (let's name them NARPs) and a device that supports ARP, running Linux (lets' name it LX). LX knows the IP and MAC addresses of NARPs. What is ...
0
votes
0answers
120 views

why iptables SNAT doesn't help to answer ARP on the vlan tagged subnet?

I'm using iptables SNAT to setup a "router" on a linux box, it suppose to do NAT for 2 subnets. one untagged subnet 10.0.10.0/24, the other one is vlan tagged subnet 172.16.0.0/24. both subnet come ...
0
votes
0answers
137 views

Ping is happening but arp is not resolved

I am seeing one interesting problem. I have setup two devices connected through lan cable over eth3 interface. Now a vlan session has been created on both the interfaces. Device 2: root@10:~ >...
1
vote
1answer
102 views

Why ARP cache is not emptied as I except it to be?

I'm trying to empirically test the time an entry stays in the ARP cache table. This time seems to be defined by /proc/sys/net/ipv4/neigh/default/gc_stale_time file and by /proc/sys/net/ipv4/route/...
1
vote
2answers
360 views

Arp request for a non-existing host in a local network

I'm wondering why I get the following result : if I try to access a non-existing host on my local network, for instance using the command ping, I see with the tcpdump arp command that there is every ...
0
votes
0answers
120 views

What causes the Linux neighbour table confirmation counter to be reset

Given three linux hosts on the same broadcast domain, the sender constantly pings an IP bound to receiver1. When moving the IP address from receiver1 to receiver2 it takes a quite long time for the ...
2
votes
1answer
83 views

Broadcast ARP query to all nodes?

I am trying to broadcast an ARP query. I want to get every node's ip and mac address updated in my system via this query. So that I can type $arp and see all the nodes on my network and their ...
0
votes
2answers
128 views

ARP packets are sent as IPv4 packet [closed]

Is it true and why? ARP packets are sent as IPv4 packet. Thanks, in advance.