Unix and Linux Stack Exchange
Unix and Linux Stack Exchange

Questions tagged [arp]

Questions pertaining to ARP (Address Resolution Protocol) a communication protocol used for discovering the link layer address, such as a MAC address, associated with a given internet layer address, typically an IPv4 address.

124 questions
31
votes
6 answers

Can one ping a NIC by MAC

I have an NIC card on a Debian machine somewhere. The machine is turned off, but I need to know whether the NIC card is turned on so that I can send a wake-on-lan magic packet later (from another Debian machine) to wake it up. I have the MAC address…
FirstName LastName
  • 555
  • 1
  • 5
  • 12
24
votes
4 answers

How do you clear the arp cache on linux?

Both: sudo ip -s -s neigh flush all And: sudo arp -d 192.168.0.102 Instead of clearing the arp cache they seem to just invalidate entries (they will appear as incomplete). Even after some minutes, the ARP cache looks like: $ arp -n Address …
blueFast
  • 1,168
  • 2
  • 11
  • 15
18
votes
7 answers

Find the IP address of a newly-booted Raspberry Pi

I've attached a Raspberry Pi running Ubuntu to my home network with a cable. It is booted up and connected to the network. The Pi has no keyboard, mouse, or monitor. If I know the IP address that was assigned to the robot, they could ssh into it. It…
pitosalas
  • 637
  • 2
  • 8
  • 17
12
votes
4 answers

Using Python and Scapy to sniff for ARP on Pi

I'm trying to use a Raspberry Pi to find ARP requests from a specific wireless device on my network. It's one of those Amazon dash buttons. Someone used this code to listen to when the dash connects to wifi. from scapy.all import * def…
user851
  • 121
  • 1
  • 1
  • 3
11
votes
2 answers

Linux does not reply to ARP request messages if requested IP address is associated with another (disabled) interface

I have a PC(kernel 3.2.0-23-generic) which has 192.168.1.2/24 configured to eth0 interface and also uses 192.168.1.1 and 192.168.1.2 addresses for tun0 interface: root@T42:~# ip addr show 1: lo: mtu 16436 qdisc noqueue state…
Martin
  • 7,284
  • 40
  • 125
  • 208
10
votes
1 answer

Get MAC address of a directly connected device

Given a Linux server with an ethernet card, another device say an unconfigured router is connected with a patch lead (or an ethernet lead cabled in a different way if needed). They're both powered up. Is there a way on the linux box to get the MAC…
Recct
  • 647
  • 3
  • 8
  • 15
7
votes
1 answer

sysctl parameter for correct ARP response

I have a server that has some VMs, but the VMs can't communicate properly with the server because the server has several interfaces, and it responds on the wrong one. Q: We know that there is a kernel parameter that can ensure that ARP responses…
LanceBaynes
  • 39,295
  • 97
  • 250
  • 349
7
votes
1 answer

ARP request with wrong IP address

I have a strange problem with a Linux router. The setup is like this: host1 === Linux router === host2 a.b.c.d --- a.b.c.e/g.h.i.j --- g.i.h.k Every five minutes host1 tries to reach host2. If host2 is down, the Linux router makes an ARP…
Mathias Weidner
  • 116
  • 1
  • 3
6
votes
2 answers

No MAC corresponding to IP in `arp` table: how to troubleshoot?

I've got a Debian 7 linux machine and a TP-link MR3020 router attached to it via ethernet cable at eth0 interface, working in WISP mode meant to make it a client rather than an access point: I also have a separate router connected to ISP and nicely…
Boris Burkov
  • 3,931
  • 4
  • 25
  • 37
6
votes
1 answer

Understanding virtual switches in Linux

I am confused by the way I have to set up virtual switches in Linux. I proceeded as follows: ip link add name br0 type bridge ip link set br0 up This should create a virtual switch called br0. Now, let's suppose I have a physical network device…
Democritus
  • 63
  • 1
  • 3
5
votes
1 answer

Best way to filter/limit ARP packets on embedded Linux

I have an embedded Linux on some network device. Because this device is pretty important I have to make many network tests (I have a separate device for that). These tests include flooding my device with ARP packets (normal packets, malformed…
matt
  • 53
  • 1
  • 4
5
votes
1 answer

FreeBSD static ARP entry when link cycles

we are trying to add a static ARP entry to a FreeBSD system. This works well with, for example, arp -S 172.16.16.9 11:54:33:A8:B2:6B . We have added this to a startup script to survive a reboot. So far so good. However, if the physical link is…
namezero
  • 153
  • 1
  • 5
5
votes
2 answers

How to prevent arp-scan from writing to syslog?

I am using arp-scan in a bash script to verify that a host is reachable. I have the script setup as a cron job that runs every minute and /var/log/syslog is filling up with the arp-scan output. I have tried -q and --quiet and I don't see that it has…
Brandon
  • 53
  • 6
5
votes
2 answers

arping equivalent for IPv6

What is an equivalent for IPv6 of arping -q -c 3 -A -I [device] [ip]? I know, there is not an arp in IPv6 and Neighbor solicitation used instead, but which linux user space tool can send such solicitation?
vasily-vm
  • 720
  • 7
  • 16
5
votes
2 answers

Why does arp -a only show some machines on my network?

I ran arp -a on a Linux server, and this is the output: [root@trnsrv1 ~]# arp -a ? (10.223.8.82) at 00:50:56:B5:75:08 [ether] on bond0 ? (10.223.11.254) at E0:5F:B9:66:A6:00 [ether] on bond0 10.223.11.254 - this is the gateway 10.223.8.82 - this…
afl
  • 69
  • 6
1
2 3
…
8 9