just a word of warning. i have a shared adsl connection - an alcatel
speed touch filter, a netgear router behind that, and then a bunch
of macs... :-) i have a dynamic id address allocated by my ISP.

yesterday i installed the latest network update for 10.1.5 which is
supposed to resolve issues with network connections after sleep, and
minor ticklings here and there. my build number is now '5566'.

after the install my connections were in fact more than sluggish.
and after a bit of sleep [my mac, not me] no connection could be
established.

i supposed that it was my ISP mushing the DNS servers as they do 
periodically
and so took this as an excuse to get some sleep myself.

this morning, no connections either. that meant 12 hours. well, they have
exceeded that length of time in the past but it is unusual so i did
various checks. my home network was ok. the filter was chatting with
the DSL filter at my ISP [TX and RX blinking] but still no connections
were getting through.

my ISP uses PPPoE and for mac os 9 they supply a tunnel-builder 
application
for connections. however on mac os x, PPPoE is native so i disconnected
the home network and connected the iBook direct to the filter.

to cut a long story short, i couldn't get a connection until in the 
TCP/IP
tab of the Network Preferences i set the Settings to Manual with an IP
number of '0.0.0.0'. [my ISP uses a DHCP server, so it should be the
Automatic Settings...] anyway, this got me connected, and when i put the
home network back into place, everything was working fine.

i doubt that many here have similar setup, nor that any of you are such
'updater' freaks as i am. but this post is designed to help anyone in
a similar sticky [and non-connected] situation.

:-j