How can I troubleshoot my Mac's ADSL connection?

June 8, 2004 5:29 PM

How can I troubleshoot my Mac's ADSL connection? A few weeks ago my download speed suddenly dropped to about 4kilobits/sec after I tried to set up a firewall. I then turned off the firewall, but the speed hasn't returned. I'm running Mac OSX 10.3.4 on an eMac with 1GHz processor and 1GB RAM (confirmed intact by profiler) on a simple ADSL router (YahooBB, the leader in Japan) with an ethernet hub. Interestingly, upload is fine at 500 kbps, and my older slot-loading iMac 350MHz is zooming along fine on the same connection at 1150kbps download speed. TCP/IP settings are simple, DHCP auto-assigns the IP.
posted by planetkyoto to computers & internet (11 comments total)

What firewall, and is it Hardware of Software?
posted by willnot at 6:12 PM on June 8, 2004

The one that's built-in under the file sharing preference panel. It's off now. I should mention that I tried switching ethernet cables and hub ports, and turning off the router and waiting. Time of day is no factor, it seems.
posted by planetkyoto at 6:34 PM on June 8, 2004

Do you have the same problem if you create a new user?
posted by willnot at 7:20 PM on June 8, 2004

Good idea, hadn't thought of logging out; however, the new user has the same slow connection. Most stuff just fails to load, even text-a-riffic Metafilter hangs for minute or times out before downloading a page. Previewing local Dreamweaver pages in any browser, they draw up just as fast as ever.
posted by planetkyoto at 7:39 PM on June 8, 2004

Hmmm.. So, I'm thinking it has to be software (since the same hardware on other systems looks good), and it must be a global setting since other users are effected. What if you trash
root>Library>Preferences>com.apple.sharing.firewall.plist and then reboot? (back it up first)

I don't know what in there could be messing with you, but it's worth a shot. You might also nose around in there to see if anything else in that directory looks like it might be suspect

Have you tried repairing disk permissions? You'd do that using the disk utility. You might also try booting into single user mode and running FSCK.
posted by willnot at 9:01 PM on June 8, 2004

Try 'sudo ipfw flush' in the terminal (hey ya never know...)
posted by nathan_teske at 9:44 PM on June 8, 2004

How are you measuring speed?
posted by skallas at 10:18 PM on June 8, 2004

OK, I tried trashing the firewall preferences, but that didn't work. The letters FSCK give me chills, as my iBook went down in flames with a kernel panic. This 'sudo ipfw flush' is something I've never heard of, it's not a joke is it?

Skallas, I ran the test at DSLreports.com a few times at different times of day. Many sites I try to load just hang and don't load. Diving back in...
posted by planetkyoto at 9:04 AM on June 9, 2004

Repaired permissions, but nothing yet. Found references for the ipfw flush, will be looking into that further, and FSCK.
posted by planetkyoto at 9:13 AM on June 9, 2004

Umm, perhaps create a new location with reverted settings? Locations are shared between users. This is kind of a guess.
posted by adamrice at 11:55 AM on June 9, 2004

Thanks to everyone for the help. It seems to be some problem with the ethernet hub. When I plugged the router directly into my computer, zing! I still don't understand what could be wrong with a simple ethernet hub, but at least I can find my way out. Gonna buy a new one today.
posted by planetkyoto at 7:12 PM on June 9, 2004