If the file is physically present, but the URL produces a '404' error from
all locations, then there is really only two possibilities:
[a] The URL is incorrect.
[b] The URL is being resolved to an incorrect IP Address.
[a] can occur if you have renamed the WSUS Server, updated the DNS, but not
properly dealt with the necessary requirements of renaming a WSUS Server.
[b] can occur if the DNS is simply incorrect, or since you are dealing with
client machines in a different forest, your FQDN may be getting resolved to
an external address, rather than an internal one.
[c] in addition, using FQDNs for internal use runs the risk that that
traffic is getting bounced through a proxy server, which is one more
possible avenue for dysfunction, and if the proxy server is configured to
block EXE downloads -- an HTTP 404 might be an expected response.
Given, however, that this behavior is being exhibited ON the WSUS Server -
I'd suggest we start by troubleshooting the problem from there, and ignore
all of the other client machines until it is possible for the WSUS Server to
see it is own locally hosted virual directory.
1. Verify that the WSUS Server can properly resolve the FQDN of the WSUS
Server to the IP Address of the WSUS Server.
2. Confirm that FQDN-named traffic is not being unnecessarily routed through
a proxy server. (Or, a simpler solution, do not use FQDN URLs for internal
use, use simple hostnames, aliased through DNS (if necessary), and ensure
that clients have properly configured Domain Name Suffixes and are properly
appending the correct Domain Name Suffix(es) in their DNS Search Order
Lawrence Garvin, M.S., MCITP:EA, MCDBA
Principal/CTO, Onsite Technology Solutions, Houston, Texas
Microsoft MVP - Software Distribution (2005-2009)
My Blog: http://onsitechsolutions.spaces.live.com
Microsoft WSUS Website: http://www.microsoft.com/wsus
My MVP Profile: http://mvp.support.microsoft.com/profile/Lawrence.Garvin