This follows previous posts about our Mac integration in our Domain.  If you have not read them, we chose the Dual Directory method (sometimes called Magic Triangle) to integrate our Macs into our existing Windows network. It takes the Macs a long time to find the network and doesn’t always find the user’s home folder.   Kevin has done some network captures using Wireshark and has learned a few things that we have tried. (He has found this book on Wireshark to be most useful.)

First, we’ve experimented with disabling spanning-tree protocol for our client ports and seen about a 20 second improvement from Mac gong sound to ‘other’ showing up the login options (indicating that it knows there is a network). This had a negligible affect on windows clients. Note: on Dell Gigabit switches this is enabling Fast Link on a client port.  We learned that from this blog post.

Secondly, his captures of a Mac booting up and attaching to the network are very interesting. Before the Mac has even sent out a DHCP request is doing multicast DNS queries with an APIPA address to find the Mac domain controller (open LDAP server). Even after it has its IP address it continues to try and use MDNS.

The next moves and nagging questions :

  • investigate having an intelligent MDNS service that proxies the inside DNS
  • investigate if IPv6 DNS might be necessary as we see a lot of IPv6 MDNS requests even from iPhones on the wireless
  • IP Helper– could IP Helper settings on the switches assist with DHCP and cut out time or MDNS in someway?
  • Is it still just an issue with .local domain that OSX might insist belong only to MDNS?

Kevin will continue to analyze the data and has bounced some of this off of his friends Lester and Eric.

If you have experienced this issue, please comment and share what you have learned!

Paul Rhodes found this article, but we would like to do some more research before going this route.  The problem we see here is for our laptop users having multicast issues when they are offsite.