Slow down in internet connection when mac online

[slarty755]

First off, I am very sorry if this is in the wrong place.

I have 50mb internet connection and have purchased a mac book with snow leopard installed for my daughter.
Now when she connectds to the internet through our router (I have tried two, a d-link n and a belkin n router) the connection for everyone in the household, two laptops two iphones and two pc's slows to a crawl, when she disconnects it speeds up.
I have searched to no avail, I have tried adding the dns servers suggested and decreasing the mtu size.
I used to be a pc system annalyst but know nothing about mac i'm afraid so any help would be greatfully appreciated

TIA

 

[old-wiz]

wonder if it might be downloading system updates to OSx?

 

[mooblie]

Agreed - might be worth trying this: leave her Mac connected overnight, so if it IS downloading anything big, it will have finished by morning.

 

[Denarius]

Agreed - might be worth trying this: leave her Mac connected overnight, so if it IS downloading anything big, it will have finished by morning.

Wouldn't it be easier just to see if Software update is running?

 

[gauchogolfer]

Can you open Activity Monitor and see what network activity is going on?

Also, make sure the IP addressing is consistent across all the computers...is she statically assigned while the others are dynamic? If so, maybe the other machines are having to wait to get new IP addresses assigned. Just a thought.

 

[slarty755]

I have had reget running and downloading and it hasn't caused this much of a speed decrease, but I will check. She is getting ip via dhcp, I don't see it would make that much difference if she was static but it is worth trying. I think I will try assigning all conncted a static ip and reserving those addresses for the mac addresses on the router, maybe it would help.
The main thing is that it is consistent, every time she connects we all slow, dead confused (

 

[Denarius]

I have had reget running and downloading and it hasn't caused this much of a speed decrease, but I will check. She is getting ip via dhcp, I don't see it would make that much difference if she was static but it is worth trying. I think I will try assigning all conncted a static ip and reserving those addresses for the mac addresses on the router, maybe it would help.
The main thing is that it is consistent, every time she connects we all slow, dead confused (

Are there any other boxes on the network that have a static IP within the DHCP servers allocation range?

Edit: Sorry, I see somebody has already pretty well said this, but another thought is to disconnect every other computer from the network apart from hers and add them back one by one, testing the performance of all machines as you go. Also, if they're all connecting via wireless, if you have a lot of machines on one access point it can cripple performance. If that is the problem, you could set up your second router as a second wireless access point and share the computers/phones between the two access points.

But another point is, when it's slow for all of the other machines is it also slow for hers?

 

[slarty755]

Well I have now assigned her a static ip and turned off ipv6 and nothing, after a very short period of time with the mac connected it all slows, for the mac also. She has been disconnected for a couple of days and all has been fine, it doesn't look like any updates or the like are downloading on her mac, but then again I don't see that it should make a difference as we have 50mb it should be able to cope. This is now getting pretty damned annoying.

 

[Denarius]

Well I have now assigned her a static ip and turned off ipv6 and nothing, after a very short period of time with the mac connected it all slows, for the mac also. She has been disconnected for a couple of days and all has been fine, it doesn't look like any updates or the like are downloading on her mac, but then again I don't see that it should make a difference as we have 50mb it should be able to cope. This is now getting pretty damned annoying.

Best put her back to DHCP then. You haven't said whether or not you've actually done software updates on her Mac. I only ask because I believe 10.6.0 did have a few networking foibles.

Are there any QoS settings available in the router. I'd point you to my previous suggestion of trying each other computer with hers on one by one to see how they behave. You can also open a session in terminal and do the following to see your network traffic. Might give a clue.

sudo tcpdump -i en0 -v

for a mac connected by ethernet or

sudo tcpdump -i en1 -v

for a mac connected by wireless.