More slow wi-fi / network (10.5.1)

Question

I am suffering a bit with my internet connection at the moment, and knowing more than a little about IP networks I found this to be DNS related. After getting no where with my ISP support my gf noted that her old powerbook (tiger) was working fine.
So I decided to keep an eye on the system.log to see what was happening (tail -f /var/log/system.log). And here is the output...
+Nov 17 17:57:46 Macintosh configd[35]: setting hostname to "Macintosh.local"+
+Nov 17 17:57:46 Macintosh com.apple.launchd[1] (com.apple.SystemStarter): Failed to count the number of files in "/System/Library/StartupItems": No such file or directory+
+Nov 17 17:57:46 Macintosh com.apple.launchd[1] (com.apple.SystemStarter): Failed to count the number of files in "/System/Library/StartupItems": No such file or directory+
+Nov 17 17:57:46 Macintosh com.apple.launchd[1] (com.apple.SystemStarter): Failed to count the number of files in "/System/Library/StartupItems": No such file or directory+
+Nov 17 17:57:46 Macintosh configd[35]: setting hostname to "Macintosh.home"+
+Nov 17 17:57:48 Macintosh mDNSResponder[23]: Note: Frequent transitions for interface en1 (FE80:0000:0000:0000:0216:CBFF:FEB8:DDBE); network traffic reduction measures in effect+
+Nov 17 17:58:26 Macintosh configd[35]: setting hostname to "Macintosh.local"+
+Nov 17 17:58:26 Macintosh com.apple.launchd[1] (com.apple.SystemStarter): Failed to count the number of files in "/System/Library/StartupItems": No such file or directory+
+Nov 17 17:58:26 Macintosh com.apple.launchd[1] (com.apple.SystemStarter): Failed to count the number of files in "/System/Library/StartupItems": No such file or directory+
+Nov 17 17:58:26 Macintosh com.apple.launchd[1] (com.apple.SystemStarter): Failed to count the number of files in "/System/Library/StartupItems": No such file or directory+
+Nov 17 17:58:26 Macintosh configd[35]: setting hostname to "Macintosh.home"+
+Nov 17 17:58:28 Macintosh mDNSResponder[23]: Note: Frequent transitions for interface en1 (FE80:0000:0000:0000:0216:CBFF:FEB8:DDBE); network traffic reduction measures in effect+
+Nov 17 17:59:04 Macintosh configd[35]: setting hostname to "Macintosh.local"+
+Nov 17 17:59:04 Macintosh com.apple.launchd[1] (com.apple.SystemStarter): Failed to count the number of files in "/System/Library/StartupItems": No such file or directory+
+Nov 17 17:59:04 Macintosh com.apple.launchd[1] (com.apple.SystemStarter): Failed to count the number of files in "/System/Library/StartupItems": No such file or directory+
+Nov 17 17:59:04 Macintosh com.apple.launchd[1] (com.apple.SystemStarter): Failed to count the number of files in "/System/Library/StartupItems": No such file or directory+
+Nov 17 17:59:04 Macintosh configd[35]: setting hostname to "Macintosh.home"+
+Nov 17 17:59:07 Macintosh mDNSResponder[23]: Note: Frequent transitions for interface en1 (FE80:0000:0000:0000:0216:CBFF:FEB8:DDBE); network traffic reduction measures in effect+
+Nov 17 17:59:42 Macintosh configd[35]: setting hostname to "Macintosh.local"+
+Nov 17 17:59:42 Macintosh com.apple.launchd[1] (com.apple.SystemStarter): Failed to count the number of files in "/System/Library/StartupItems": No such file or directory+
+Nov 17 17:59:42 Macintosh com.apple.launchd[1] (com.apple.SystemStarter): Failed to count the number of files in "/System/Library/StartupItems": No such file or directory+
+Nov 17 17:59:42 Macintosh com.apple.launchd[1] (com.apple.SystemStarter): Failed to count the number of files in "/System/Library/StartupItems": No such file or directory+
+Nov 17 17:59:42 Macintosh configd[35]: setting hostname to "Macintosh.home"+
+Nov 17 17:59:45 Macintosh mDNSResponder[23]: Note: Frequent transitions for interface en1 (FE80:0000:0000:0000:0216:CBFF:FEB8:DDBE); network traffic reduction measures in effect+
As you can hopefully see there are two (possibly related) problems here that keep repeating every 30-60 seconds:-
First, it would seem that launchd is trying to do something in /System/Library/StartupItems which no longer exists (Is this an error on my machine, or normal for 10.5.1?)
Secondly, for what ever reason, my network or DHCP seems to keep switching my macbooks name from Macintosh.local to Macintosh.home, and putting into force some sort of traffic reduction!!!
I am using a BT home hub for wi-fi at the moment, I will check the wired connection shortly too.
Can anyone else shed any light on this? seems to have started since the 10.5.1 update!

Answer 1

FWIW, I had a similar problem. I'm running an Airport Extreme network with two Airport Express' setup as a WDS. Clients are my MacBook Pro 17" (Intel), my wifes Dell laptop (sorry, can't get her to change), and my TiVo. My network access from my MacBook (10.5.1) was ridiculously slow. I'm on Comcast Cable.
So... this morning, after spending some time on the discussions, I went into my Network Preferences and set IPv6 to "off" for all my networks. Airport, wired, everything.
Bingo. Speed is back up to a normal, reasonable level. I'm happy again. Prior to this change, I was getting less than dial up speeds through my network on my Mac. Now I'm back up to what I feel are reasonable speed levels given that I'm quite far out on the end of my cable providers loop.
Hope this helps!
Tom