Loose internet connection but still connected to router?

[AshP]

Hi all,

I have searched hi and low all over the web and have not come across anyone who seems to have an answer to my problem..here goes (sorry if the post is a little long):

I am trying to run my Macbook Pro (Tiger) on a small office network.

The network is run off a 2wire BT Business ADSL router which provides internet connection and acts as a hub for the office. The office network consists of:
1x server running Windows SBS 2003 connected through ethernet
1x Desktop XP Pro PC connected through ethernet
3x Desktop XP Pro PCs connected wirelessly
1x HP Officejet Pro printer connected through ethernet
1x DLink DNS 323 NAS drive (which is used by the server for backup) connected through ethernet
Occasionally there are also some XP Pro laptops which are in the office and just use the router wirelessly to get onto the internet - they work with no problems.

Now I can connect my MBP to the router fine (as in once it is connected i can access all the shared files, access the internet & even managed to get Entorage to sync with the server(!)). But the odd thing is after a certain time period I will loose the ability to use the internet. Sometimes it is 1 minute sometimes it will work for 20 mins but I don't think it has ever stayed on much over 30 mins. What I don't understand is that although my internet connectivity is lost, I am still connected to the router and can access the internal network (Entorage continues working, can copy files from server etc). I can also still ping the server and the router.

To make things worse I convinced my boss that Macs are the future and he bought a Macbook (running Leopard) last week which is suffering from the same problem & another problem which I will cover in a different thread (will post link later). He is not a happy person to say the least.

This leaves me baffled as to what the problem is as the Windows machines do not appear to suffer from it and everything will work fine for a brief period. The only way to fix the problem is to turn airport off and back on again.

I know this sounds like an impossible problem but I know there must be some sort of genius out there who has the answer...

I just hope they find this thread!

Thanks for any help in anticipation!!

Ash

 

[belvdr]

Just because you are connected to your wireless (your local LAN), does not necessarily mean the router has a valid IP and/or is routing packets properly. To bring this down a notch, consider your wireless as just a connection to your private LAN.

Have you checked your DSL router to ensure the lights are as they should be (meaning the DSL router trained properly)?

Also, check your router to see what the WAN IP is when the connectivity is lost.

 

[ChrisA]

Is your Mac getting it's IP address from the router via DHCP or are you setting it by hand? If by DHCP is this working right, does the router have enough IPs to hand out? Is there a DHCP status table that you canlook at inside the router? Is the router restricting access by MAC address? (Yes MAC not Mac.)

 

[corbywan]

It's possible it's a DNS glitch with your ISP as well. You might try manually assigning the DNS info to the computers having the issue. You could also try to ping stuff outside of your network via name and IP. Try pinging 204.147.80.5 when you can't surf the net but can access your local network. If that ping works your connection to the internet is there, but there is probably some kind of DNS glitch.

If it turns out to be a DNS thing I would look at using opendns.org instead of your ISP's servers as opendns seems very reliable.