NAT Problem - DNS OK

[lisco]

I have two clients and one server, 3 weeks ago, both were OK. Today, without any configuration change, one client doesnt access the Internet. The other is OK.
I sniffed the network and I see that the problematic client send your DNS requisition to the server and get the IP address correctly. After that, the client tries to go to internet directly, without going to the server.
Internet Explorer settings are equal for both. - Detect Automatic Proxy Settings

Client OK:
IP: 192.168.58.251
Mask: 255.255.255.0
Default Gateway: 192.168.58.83
OS: Win98
No wingate Client

Client "problematic":
IP: 192.168.58.252
Mask: 255.255.255.0
Default Gateway: 192.168.58.83
OS: Win98
No wingate Client

Server:
IP: 192.168.58.83
Mask: 255.255.255.0
Default Gateway: 192.168.58.1 - Goes to other server (not wingate) that uses nat/proxy - ISP server
OS: Win98
Wingate 5.2.3

I tried to install Wingate Client, delete the history, reinstall wingate............

So, one client access the internet and the other not!

All logs are clear but the NAT log:

03/25/04 12:27:23 Debug: NAT error message code FFE0B40B, context 1412 OutICMP=0, InICMP=0, OutUDP=0, InUDP=0, OutTCP=762, InTcp=88
03/25/04 12:27:23 Debug: NAT error message code FFE0B40B, context 1420 OutICMP=3, InICMP=18, OutUDP=0, InUDP=0, OutTCP=0, InTcp=0
03/25/04 12:27:23 Debug: NAT error message code FFE0B40D, context 1426 Total locked memory in use is 190500
03/25/04 12:27:23 Debug: NAT error message code FFE0B40E, context 1433 Unknown Frames = 0, Status Queue Size = 128
03/25/04 12:27:26 Debug: NAT error message code FFE0B407, context 55 TCP checksum failed
03/25/04 12:27:28 Debug: NAT error message code FFE0B40B, context 1412 OutICMP=0, InICMP=0, OutUDP=0, InUDP=0, OutTCP=762, InTcp=88
03/25/04 12:27:28 Debug: NAT error message code FFE0B40B, context 1420 OutICMP=2, InICMP=18, OutUDP=0, InUDP=0, OutTCP=0, InTcp=0
03/25/04 12:27:28 Debug: NAT error message code FFE0B40D, context 1426 Total locked memory in use is 190500
03/25/04 12:27:28 Debug: NAT error message code FFE0B40E, context 1433 Unknown Frames = 0, Status Queue Size = 128
03/25/04 12:27:29 Debug: NAT error message code FFE0B406, context 102 UDP checksum failed

[adrien]

The NAT log contains mainly statistical messages about the amount of memory in use in the ENS kernel driver.

However those 2 messages about TCP and UDP checksum failures are interesting. Do you see packets on your LAN with bad checksums?

As for your client machines, are they running IE6? IE6 can do some weird things, and ignore manually set configurations.

Also are both client machines using the same DNS server (the WinGate server).

Automatic proxy detection uses firstly DNS to lookup a name called WPAD. WinGate treats DNS lookups for "WPAD" specially and returns its own IP address, the client then makes a special http request to retrieve the proxy configuration file from WinGate.

However, we have found that if you have run the network setup wizard on XP, then IE6 can behave strangely if it has a default route. It may consider it has direct access and decide not to use a proxy even if you have configured it to use one.

Adrien