MacBook would not connect to 3G mobile WiFi (MiFi) router at specific location.

Here's an interesting one which I thought I would post perhaps to offer a potential solution to someone with the same problem but also get people's thoughts.

I had a problem where my MacBook would not connect to my Huawei E586 MiFi router when I was in the office. Instead, when I tried to connect I got a timeout error.

The reason why I think the problem was with the MacBook was becuase.

- I recently changed the router and the same problem kept occuring.

- Other devices, such as my iPhone and PC laptops in the office were able to connect fine.

Strangely when I get back on the train or am at home it will connect fine.

The problems was eventually solved by,

- Removing all security on the router, this changed nothing.

- Manually configuring local IP settings to 192.168.1.2, 255.255.255.0 & 192.168.1.1. Router is set to dynamically assign on that sube net from .100 through to .200. Just configuring the IP address manually did not work.

- Adding the DNS entry of 192.168.1.1 in the respective panel in system preferences as it was not there. Interested to know potential reasons why my MacBook is not detecting and putting these in automatically as I have never had to do this before?

I also set up a separate location from the Automatic so I could switch back to DHCP easily when I am on my wireless at home. When I changed back to this in the office though the connection worked fine making me thing I've 'jolted' some corrupt configuration file into action through the above tinkering.

I have a few, loose and relatively untested theories.

The first was that there was something in the office like a DECT phone or other wireless netowork that was interfering with the connection but I would be inclined to discount this for the reason that all other devices we tested connected perfectly.

The second is that there was a corrupt configuration file or security setting that was corrected by a part of my tinkering. This again would not explain why it worked perfectly well at other locations.

The third was that the office location which is open plan and houses 20 people does have a range of other, more modern, devices in there which may have been trying to connect to the router and interfering with my 2 year old laptops connection attempt. At one point when I was troubleshooting I did notice that the connected devices table going crazy trying to assign an IP to a device with the MAC address of my laptop and coming up with a range of crazy numbers inc. 0.0.0.0 and 192.168.1.100 (which was at the time assigned to my iPhone). If the error comes back I will try and get some video of this.