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Erratic conduct of browsing over internet with a dsl moden and a router

Jewels1
Jewels1 asked
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Last Modified: 2010-03-17
Hi there, I hope you can help me figure out a solution for this annoying problem. I have the following setup: 256 kbps>>dsl modem>>SMC router>>switch>>7 PCs. The machines work fine when it comes to downloading files and information. But  the browsing is very erratic. Some pages wont show and if they do they lack elements (package loss maybe?). Others open very quickly and others just wont open at all.  At first the problem seemed to be caused by a communication mismatch between the router and the NICs on the computer. I manually set the NICs to 100 Fullduplex and the problem seemed to dissapear for one or two days. I realize the setup must be the same on the router port and the NICs but there is no way for me to verify the router port configuration. The thing is my LAN started working beautifully for a while but then dropped again. Again, the downloading has no problem, but the browsing is back to normal (that is lousy). When I connect the dsl modem directly to a computer the problem dissapears and when I connect to the internet using the router and a dialup connection using a different modem the machine works fine (except for the constant disconnecting).  Could the problem be between the router and the modem? I tried resetting the router a few times to no avail. All the machines have the 100 fullduplex configuration. This is the second SMC router I buy. The other one went to warranty. It seems the latest firmware is somehow defective (according to the technician) and there is no way to go back to the default version. I reaaly doubt this one is defective. Any idea pleasssee. This is killing me.
Thanks
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Try setting the MaximumMTU of the router to 1492.  DSL with PPoE tends to add an extra 8 bits for PPoE authentication, thus making it 1508 if you don't change it.  This happens A LOT to DSL connections.  Although it might not be your problem, it is certainly a good practice regardless.

- Info

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Commented:
Thanks infotrader. Done. I had some of the machines connected to the switch, while other were directly connected to the router. It occured to me that the duplex configuration of both devices could be different, so I connected them all to the switch to make sure everything went on 100 full duplex. The thing got better. I am using Pingplotter to monitor the performance on the network right now. So far the browsing is quite acceptable on all the machines (except for a few pages that will simply not show on screen). The problem is when I make a download. Ping time goes from a fairly acceptable 100ms to 700-1000ms. I am not doing multiple downloads on the network. Just one. I/m puzzled. Any idea? tnx
CERTIFIED EXPERT

Commented:
Try running this tweak test from one of the computers

http://www.dslreports.com/tweaks

It may give a indication to your problem.
Commented:
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