Article ID: 169268
Article Last Modified on 6/23/2005
APPLIES TO
- Microsoft Internet Information Server 3.0
This article was previously published under Q169268
We strongly recommend that all users upgrade to Microsoft Internet Information Services (IIS) version 6.0 running on Microsoft Windows Server 2003. IIS 6.0 significantly increases Web infrastructure security. For more information about IIS security-related topics, visit the following Microsoft Web site:
SYMPTOMS
When you try to connect to a site via FTP, you may get the following error message after a few minutes if the Internet Information Server (IIS) is configured with more than one default gateway:
This may also happen only when you try to connect via FTP using a slow link (for example, a 28.8k modem connection) to a server that has more than one default gateway.
CAUSE
The IIS computer should have only one IP default gateway. The IP address of the default gateway should be configured on the external network adapter card only.
This requirement is a result of the basic architecture of TCP/IP. Only one default gateway must be defined on a host that resides on two or more non-connected networks.
If IIS server is configured with more than one network interface, it is connected to two networks that are by design non-connected.
A default gateway is a router that is supposed to be used for all traffic that has no specific route. If you have two default-gateways, the IIS server TCP/IP stack will assume that they lead to the same set of networks. This will cause the IIS server to send Internet traffic to the internal network, or internal traffic to the Internet.
WORKAROUND
Remove the default gateway from the advanced TCP/IP settings of the internal network interface on the IIS server and define static routes to the internal network segments.
For additional information, please see the following Microsoft Knowledge Base article:
161380 : Only One Default Gateway Allowed On Proxy Server
Because no default gateway will be defined for the internal network, you must add static routes using the Route Add command. These routes can be made persistent by using the -p command switch.
MORE INFORMATION
For additional information on adding static routes to the routing table, please see the following:
- Type route /? for additional command switches.
For additional information, please see the following Microsoft Knowledge Base article:
140859 : TCP/IP Routing Basics for Windows NT
Additional query words: proxy internet server timeout connect fail winsock ftp iis
Keywords: kbprb kbusage KB169268
