View Full Version : mac loses ethernet connection..take a look

06-26-2003, 09:47 AM
so this is a problem I had encountered a while ago and have seen it on mvarious machines throughtout that time...

Problem this has been mainly on Power Macs all models both OS 9+X...and lately on Powerbooks....when the mac is hooked to a dsl/t1 any broadband connection and the connection is removed...and then reseated there are times when it act as if there is no connection/ no card nothing it gives and invaild ip address 169.whatever... So my solution has been to restart and reseat the cable and after many trys it seems to work...This posted in varying degrees all over the board...here is a link to one instance and it is not the provider that is the problem

Let me know what you think


macfixit (http://www.macfixitforums.com/php/showflat.php?Cat=&Board=Forum7&Number=472641&page=3&view=collapsed&sb=5&o=&fpart=1http://www.macfixitforums.com/php/showflat.php?Cat=&Board=Forum7&Number=472641&page=3&view=collapsed&sb=5&o=&fpart=1)

06-26-2003, 11:17 AM
Do you have just a single host at home?

I've heard often enough of these sorts of flakey over-the-net via DSL or cable-modem DHCP setups that it seems so well worth it to...

One thing you can do, whether it's just one host or many, is to add a router between the DSL modem and your "home net" side. If your provider insists on registering the MAC (hardware) address of the host at your end, you'll have to have them switch from the Macintosh's MAC address to that of the DSL router.

I've had very good luck with a Linksys router.

ISP -- DSL modem -(E)- Linksys -(I)- Mac and other hosts


-(E)- is the external address area with an IP address assigned via DHCP to the WAN interface of the Linksys.

-(I)- is your internal "house net", now far more fully defended by the firewalling in the Linksys.

The Linksys will, by default, use the IP address on its LAN interface to the -(I)- network. When set up for DHCP, it will happily assign addresses starting with 192.168.1 to other hosts on the internal network.

However, you will not be required to use DHCP to get IP addresses on your Mac and other internal hosts; you can assign them manually if you wish, and that's a lot more stable. Set up the first Mac like this:

name_servers: (load what you saw when it was using DHCP)

and that host never needs DHCP again.

Just sorta in passing I mentioned that you are "now far more fully defended by the firewalling in the Linksys", and that's actually a MAJOR benefit and worth the less-than-$100 costs of the router. No outside intruder can get IP traffic to your internal host(s) unless programs on those hosts are currently reaching out through the firewall to the external host. Big time security defense!

You'd better make sure before trying this approach that your provider won't refuse you service if the host at your end is a router instead of a 'puter. Others with service from the same provider may be able to help you there. For us at my place, we have a Linksys at our end of the broadband fronting, errr, 8 Macs, an ABS, and a PC and, were I to power it up, a Sun running Solaris, with two separate wireless nets in play (one from the ABS and one from the Linksys, itself).


06-26-2003, 11:26 AM
It might help to know if you have a router. Personally, I dropped cable because it dropped too often.

My DSL is rock solid and easy to re-establish. No need to do anything, 10.2.6 does it automatically.

Setup a different Network setting, switch to it and back and hit Apply sometimes helps.

Could be their end rather than yours.
Could be a splitter, a UPS filter you use.
Could be weak or poor line quality.
Distance from switch or CO.
Try a different modem.
You should be through RJ11 filter on a good surge protector.
Replace the cables and phone wire.
I bought some quality 50 ft wire for dsl.
Also had the phone company out to replace wire from utility poll to the network interface, and from there to inside box.
Are you using 3 wire? Make sure you do. When I had two lines, I made sure that they took out the existing wire and put in a six wire line.

Inotherwords, all the normal troubleshooting things you normally would do.

Sometimes it helps, but in reality, especially with 102.6, you should not need the search and DNS primary and secondary.

I would make sure you ahve the latest Open Transport extensions or OS version. YOu can extract extensions from 9.2.2, and Classic gets newer versions installed the first time used with a new version of Jaguar.

06-27-2003, 06:19 AM
There is a router in the location where I was having the problem yesterday it is a T1 line...the vast majority of our macs work fine .....but the issue does come up often. I am not to sure if it 3 I'll check into that...I have had this happen at home...before I had a hub..I would just pull the ethernet when I needed it for a particular computer...did not like that...so it was suggested I by a hub....then the problem became 2 macs sharing and ip address which apparently is not possible...so I paid extra $$ to Time Warner for 2 seperate ips and now that setup is fine.. I see people w/ this problem popping up here and there and does not seem to be any real solution....I guess I'll enjoy the working connection for thr time


06-27-2003, 07:24 AM
Most people now opt for a router, and most routers now have switch capability (built in 10/100 hub). use to be a router was $100-200 and switches were equally expensive. Now, you can find a router/switch for $50 and it makes it all effortless, seamless, no cross-over to worry about, and only one IP address and the router assigns an internal IP to each computer.

07-09-2003, 03:35 AM
Thanks guys for looking at this...and I am still working on the problem! So it came up again with a Power Book G4 867...it was working fine one day...when it was moved and plugged into a functioning port...nothing just the 169 IP address. What is strange about this is there is no real solution to the problem...it just seems to spring up here and there especially with powerbooks. So then I hook my G4 500 and it is up and running like it should ...very strange


07-26-2003, 02:02 PM
...when it was moved and plugged into a functioning port...nothing just the 169 IP address.

Did you plug it into a port that had been empty for awhile, or did you replace a host in that port? Was it a different port leading to the same switch you had been on prior to moving? Switches cache the hardware addresses on specific ports to speed their dispatch of packets, so the switch may have been sending traffic for you PB down the line where it used to be connected, even though accepting traffic from your PB on the line where it was currently plugged in.

Second idea: when moving a PB, I always hop into the Network Preferences and turn off all interfaces (actually, I have a NetPref named "offline" with all interfaces unchecked). Then, before sleeping the PB, I switch location to "offline", then close the top. When I arrive at my next location, wake up and switch network location to whatever's correct for the new location.