(Presumed) DNS problem

I have a problem that I believe is related to my ISPs DNS service, but I’m not sure, and would appreciate any advice you may have. Here’s the situation:

I’m working in China, and have taken advantage of their incredibly cheap ADSL Internet service. The commissioning and installation of the ADSL was arranged by my factory, and the people there aren’t too computer literate, so I don’t think I’ll get an answer out of them. As for the 163 people (my ISP), well, the engineer who came to install it insisted that we run an installation programme from CD on the iBook to set it up. The programme was one of those ending with .exe? When we got a higher grade of engineer to come he told us (via translation) that the CD was to install PPP over Ethernet, so we skipped that and just configured the built-in PPPoE on the Airport. For the first few weeks the service worked fine, but it is just in the last two weeks it has become almost unusable.

The problem I have is that any Internet service seems very intermittent. Web browsing will commonly come up with “The specified server could not be found.? If this is retried (often in excess of 10 times), it may eventually connect to the site. The same behaviour is observed with the Network Utility, for example when Ping-ing. It will report “Unknown Host? but if you are persistent, it will eventually manage to ping the host. What got me to thinking it was a DNS problem was my e-mail problems. Again, e-mail was very intermittent, but when I replaced the server names with their IP addresses, the problem went away. Also, with web browsing, you can try for ages to access a site without success, but enter the IP address in place of the server name, and you get it served up at ADSL speed.

The hardware set-up is as follows:

* iBook running OS X (10.1.2) connects by Airport card to Airport Base Station
* Airport Base Station is plugged by RJ45 into Ethernet hub
* Ethernet hub has ADSL modem attached to “uplink?port by “straight-through?RJ45 cable with “uplink?button pressed in.

* The iBook is set to connect to the Internet using TCP/IP configured by DHCP.
* The Airport base station is set to connect to the Internet using PPP over Ethernet, and set to distribute IP addresses, with Airport clients sharing a single IP address (using NAT). I’ve also checked for Ethernet clients to share the IP address using NAT, as at some point I want to connect my Windows 2000 machine using the Ethernet hub (but haven’t tackled that yet)

At the moment I have no entries in my DNS fields in either the Network System Preference or the Internet pane of the Airport Admin Utility.

To further complicate matters, I believe my ISPs domain is 163.com (the user name format for ADSL is xxyyzz@163.gd, and .gd doesn’t seem to exist as a TLD, but it does make sense as I’m in Guang Dong province). Previously I’ve tried IP addresses for the name servers that Whois reports for 163.com (NS.NEASE.NET, NS2.NEASE.NET), but with no improvement.

I think what I need is to test the system using some other DNS service, but my limited attempts haven’t worked. Any advice as to further diagnose the problem, and how to go about fixing it would be appreciated.

Thanks in advance

Gareth

PS: I know it’s bad form, but can any replies be copied to me via e-mail, (gareth.crapper@dial.pipex.com) because as you’ve read, my web access is, to say the least, sporadic, whereas the e-mail at least does work.