Why so many NDP entries for iPhone?

  • I (unfortunately) just got an iPhone from my employer. I'm an android user so not familiar with iOS. Phone is running iOS 11.0.2, if that makes any difference. I've noticed that there are numerous entries in the NDP table for this device, multiple 10s of them. I've seen a few entries at a time for a specific MAC address due to privacy addresses, but never so many for a single device. Just to see what would happen, I tried deleting them, but they did not go away, even with the device turned off. (I'm running pfsense 2.3.4 P1.) The only way I was able to get rid of them was to SAVE, APPLY the LAN interface. They disappeared, only to come back. This isn't a big deal, but I'm just wondering why this device seems to uniquely have so many NDP table entries.

  • Not sure why your iPhone would have so many NDP entries. I have an iPhone and an iPad, and as with most devices on my network, they have only two NDP entries… one for the link-local address, one for the IP address being received via DHCPv6.

    It's possible that if you have SLAAC enabled (Unmanaged or Assisted modes in the RA settings), the phone could be changing its SLAAC privacy address frequently enough that it keeps multiple entries.

  • I'm using assisted. The strange thing is that other iphones that connect do not seem to have this issue, only mine.

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