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Questions tagged [arp]

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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What happens if two machines respond to an ARP "who is" request?

I am only recently learning about the nuances of networking, but if a malicious user responded to an ARP "who is" when they should not have, what happens?
cabbagebot
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How do I prevent excessive ARP requests sent from Windows Server 2003?

OK, I've scoured the 'net already for possible solutions and have found none. Maybe you guys can help me. I have a Windows Server 2003 setup, with a fixed IP on a routed LAN, standard /24 network. The server works fine, with the exception of one…
Mark
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Should a Dell 5424 switch have an arp entry for every machine connected to it?

I've got a Dell 5424 with about 20 machines directly attached to it. I did a ping sweep of my network (and got answers from all 20), then went to the CLI of the switch and did show arp. To my surprise, I only see two arp entries: one for my…
Bill Weiss
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Why need to send ARP to ask for MAC address when IP address is already unique?

In the usual networks, since every host has a unique IP address recognised among the stations in the network, why is a MAC address still necessary? Suppose a station A wants to send to Station B. Station A knows Station B's IP address. But Station A…
xenon
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how can I stop my sonicwall TZ-210 (SonicOS Enhanced 5.5.1.0-5o) from responding to arp queries on the wan subnet?

My sonicwall TZ-210 is answering arp queries on the wan subnet (which my isp doesn't like), basically mapping all the wan ips to its own mac address, causing network havoc since it is not set to route those back to the main isp gateway. How the heck…
IsaacB
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How can I fix a bad arp entry?

I'm just guessing that arp is my problem... I have a linux drbd server cluster set up, and due to some power issues had to unplug the switch that connects the two servers. As a result, both servers became primary and took the same IP address for…
Brent
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Linux bridge responding to arp on wrong interface?

I'm trying to build a silent bridge for monitoring purpose. My computer is running linux 2.6, brctl 1.4 and has 3 NIC: eth0, with an assigned IP, used for SSH maintenance eth1, and eth2 , the 2 ports of the bridge br0 all is set in…
dev.pollux
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Wireshark arp packets

In wireshark, after capturing some arp packets, what is the significance of all 1's in the destination field. of an Ethernet II frame?
thehollow89
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Linux: What causes static ARP entries to flush on link down

This is a question about a difference in networking behavior between Debian Buster (kernel 4.19.0-18) and Debian Bullseye (kernel 5.10.0-9). On Buster, proxy arp entries survive if the link on the interface goes down. On Bullseye they…
roelvanmeer
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why doesn't arp-scan find any devices when nmap does?

When I run nmap -sn 192.168.0.0/24 I get the result: Nmap scan report for 192.168.0.1 Host is up (0.16s latency). Nmap scan report for 192.168.0.103 Host is up (0.19s latency). Nmap scan report for 192.168.0.124 Host is up (0.11s latency). Nmap…
Qualphey
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NIC bonding on Linux in redundant network topology

I want to implement NIC bonding on Linux server in redundant network topology as shown in the network diagram below. Network topology Both interfaces of the Linux server fa0 and fa1 would be in one bond with mode active-backup, so only one of the…
ananetworking
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Why do some unknown hosts show up with nmap option-sL , and not with -sn [and do I need to worry about them]?

Initial Disclosure I am not a network engineer and my expertise in this area is low. Background while using nmap 7.70 with nmap -sL to look for the IP address of a known device on our local network [behind VPN and firewall], I noticed two entries…
Mister October
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How to fix the network after ARP poisoning attack?

I was running a program called morpheus: https://github.com/r00t-3xp10it/morpheus. It is a github project which allows ARP poisoning attacks, MITM attacks etc. I was running a arp spoofing/phishing attack (for the local network) and my computer…
bitDrop
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Weird answer of linux DHCP server to gratitious ARP causes DHCP failure

This is a problem, that I ran into recently on a quite heavily configured linux server. This machine runs Samba as an Active Directory Domain Controller, a mail server, a web server, two virtual machines (using KVM/QEMU, and connecting one of their…
Kai Petzke
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Does Loopback able to support all TCP/IP protocols

Does a Windows loopback adapter supports ACD and duplicate IPs. Say we have a code that supports full TCP stack and we bridge the program to loopback using PCAP. If in case I set both the address same - is it the right way to test ACD? Do we need…
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