Ethernet connection with router drops

Frida

Frida

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I have recently upgraded to ADSL broadband. I have a 4-port ethernet ADSL modem (NetComm NB1300 Plus4) which is connected to a G4 with a Sonnet 1.4GHz processor running 10.2.8. When modem first is turned on it connects to the net and computer fine but after 1/2-1 hr it drops the ethernet (LAN) connection so the computer's connection with the net drops. Turning the modem off and on again re-establishes the connection but it drops again after 5-10 min. The longer the modem has been on the shorter the connection seems to last. I have a double adapter on the phone line, the second one going to an EFTPOS machine and on to a phone. A line filter sits between this line and the double adapter. A second line filter sits in a different room between the wall and a cordless phone. According to the internet provider the modem's connection with the net doesn't drop, only the ethernet connection with the computer. Any suggestions?
 
So the modem has a built in router? What is actually getting the WAN IP? The modem or the computer? Perhaps the easiest way to tell would be to post where you supply the connection information. I am assuming you connect via PPPoE, so did you set PPPoE up on your mac or on the modem + router?

If you configured the router to connect then I would check your G4's IP when it is connected to the internet. Make a note of it, then check again when the net cuts out. If it hasn't changed I would say it is something with the router. Try pinging the router (change the last octet of your IP to a 1. e.g. if your mac has the IP 192.168.0.100, then ping 192.168.0.1 If you get a responce then the connection between your modem/router and mac should be fine.

Its confusing though, I have never seen a DSL modem that has a built in router/hub/switch.

Perhaps you should try removing all the extra junk and just plug the modem into the phone line directly. Are you supposed to put the filter before the modem or is that only for lines that are for phones? I can't remember, it's been so long since I setup my moms DSL.
 
Does your ISP assign your modem a dynamic IP address, and does the connection drop only when your Mac is inactive? 'Cause I had a similar problem when I had DSL; if I wasn't surfing for a while my connection could cut out, even if my Mac was busy playing audio streams. As my ISP explained to me, while my modem's connection to the net remained active, its IP address could be re-assigned during periods of [seeming] inactivity, as traffic demanded.
 
You also mentioned that a line filter existed between "this line" (which I assume is the line to the DSL modem) and the double adaptor. If so, remove the filter -- the filters are only needed on every device other than the DSL modem. There shouldn't be a filter anywhere on the line from the wall to your DSL modem.
 
Thanks for your suggestions. Initially I had a static IP address with just an ethernet cable. The ISP suggested changing to DHCP and let the DHCP server assign the address. That did nothing. I then opened the SystemProfiler and the Console log which was very strange. It said "PPPExec(PPP_STATUS) failed: status = 19" followed by "CFPropertyListCreateFromXMLData(): plist parse failed; the data is not proper UTF-8. The file name for this data could be:" and then suggested all kinds of applications not related to the net at all. I had a different problem a few years ago with strange freezes and messages saying I had to restart the computer. The problem then was a preference file called "com.apple.loginwindow.plist". I deleted that again now and -touch wood- so far the connection has been stable for over an hour. Still, I won't hold my breath. I'll keep you posted.
 
Back again and the problem is finally solved! After system scans, permissions repairs, cable replacement, disk re-initialisation and clean system installs the problem persisted. NetComm finally agreed to replace the modem and the new one works like a charm! No system problems after all. how frustrating was that. :mad:
I have heard that computers are supposed to make life easier, has anyone had any experience with that?! :D
 
Welcome to my world of network trouble shooting. The problem wasn't the computer, it was the modem. Intermittent problems are the hardest network problems to trace down. I wish there was a faster way to trace problems (like you had) down. I am glad you found the problem though.
 
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