I'm having some odd wireless networking problems on a Lenovo T400 I was recently given in the office. I do get connected to the office's wireless router, and I do get online, but everything is really very slow and unreliable.
Connections are dropped randomly and often, so that, for example, if I try to access any web page, or download some software (directly from its web page, or using yum or the GUI to add or remove software), I often have to try again and again, stop and restart, and after loads of error messages, eventually I *might* get through. It took me the whole morning to download a 100Mb file yesterday!
The Linux distro I installed is Fedora 12. This is the relevant bit of the output of lspci -v:
03:00.0 Network controller: Intel Corporation PRO/Wireless 5100 AGN [Shiloh] Network Connection
Subsystem: Intel Corporation Device 1211
Physical Slot: 1
Flags: bus master, fast devsel, latency 0, IRQ 31
Memory at f4300000 (64-bit, non-prefetchable) [size=8K]
Capabilities: [c8] Power Management version 3
Capabilities: [d0] MSI: Enable+ Count=1/1 Maskable- 64bit+
Capabilities: [e0] Express Endpoint, MSI 00
Capabilities:  Advanced Error Reporting
Capabilities:  Device Serial Number 00-22-fa-ff-ff-bd-6d-fa
Kernel driver in use: iwlagn
Kernel modules: iwlagn
This is the output of ifconfig:
wlan0 Link encap:Ethernet HWaddr 00:22:FA:BD:6D:FA
inet addr:172.17.130.178 Bcast:172.17.130.255 Mask:255.255.255.0
inet6 addr: fe80::222:faff:febd:6dfa/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:47098 errors:0 dropped:0 overruns:0 frame:0
TX packets:33285 errors:0 dropped:0 overruns:0 carrier:0
RX bytes:46675331 (44.5 MiB) TX bytes:5391619 (5.1 MiB)
This is the output of iwconfig:
lo no wireless extensions.
eth0 no wireless extensions.
wlan0 IEEE 802.11abgn ESSID:"router3b"
Mode:Managed Frequency:2.472 GHz Access Point: 00:24:B2:4B:AB:03
Bit Rate=1 Mb/s Tx-Power=15 dBm
Retry long limit:7 RTS thr:off Fragment thr:off
Link Quality=69/70 Signal level=-41 dBm
Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
Tx excessive retries:0 Invalid misc:0 Missed beacon:0
pan0 no wireless extensions.
Any suggestion would be really appreciated.
EDIT: Good grief, that's so annoying. It took me a dozen attempts just to log in to linuxquestions, another handful to get to this forum, and a good ten minutes to post this. And accessing the search function for some reason is out of the question - I get time outs and errors all the time! Grrr, so annoying.