Hot Downloads

Welcome, Guest
Username: Password: Remember me

TOPIC: Unicast ARP

Unicast ARP 7 years 5 months ago #30110

  • RA1313IT
  • RA1313IT's Avatar
  • Offline
  • New Member
  • Posts: 19
  • Karma: 0
I recently was looking at some packet captures on my network when I realized something that seemed a bit strange to me. There was Linux machines (namely Ubuntu) that were sending ARP requests for machines and the frames had a destination MAC address of the actual machine. I checked the ARP cache on these machines and they of course had the correct MAC address in it's cache.

I was always taught and under the impression that ARP requests were always broadcast (destination FF:FF:FF:FF:FF:FF) It is as if since the machines had it's MAC address cached, it would not broadcast these frames unless the ARP cache was cleared. I verified this by deleting the ARP entry, and I viewed the first ARP request as broadcast, and subsequent ones unicast.

I guess this makes sense to reduce broadcast traffic, and it may be something that only Linux incorporates. Does anyone know the source of this behavior?
The administrator has disabled public write access.

Re: Unicast ARP 7 years 5 months ago #30112

  • S0lo
  • S0lo's Avatar
  • Offline
  • Moderator
  • Posts: 1577
  • Thank you received: 7
  • Karma: 3
Interesting, It indeed seams that some implementation of linux do that, although I'm not sure here. insecure.org/sploits/arp.games.html
Studying CCNP...

Ammar Muqaddas
Forum Moderator
www.firewall.cx
The administrator has disabled public write access.

Re: Unicast ARP 7 years 5 months ago #30173

  • RA1313IT
  • RA1313IT's Avatar
  • Offline
  • New Member
  • Posts: 19
  • Karma: 0
Anyone else know anything about this? Is this normal?
The administrator has disabled public write access.
Time to create page: 0.074 seconds

CCENT/CCNA

Cisco Routers

  • SSL WebVPN
  • Securing Routers
  • Policy Based Routing
  • Router on-a-Stick

VPN Security

  • Understand DMVPN
  • GRE/IPSec Configuration
  • Site-to-Site IPSec VPN
  • IPSec Modes

Cisco Help

  • VPN Client Windows 8
  • VPN Client Windows 7
  • CCP Display Problem
  • Cisco Support App.

Windows 2012

  • New Features
  • Licensing
  • Hyper-V / VDI
  • Install Hyper-V

Linux

  • File Permissions
  • Webmin
  • Groups - Users
  • Samba Setup