Load Balancing or NAT Can Affect Relative URL Generation (304088)



The information in this article applies to:

  • Microsoft Internet Information Services 5.0
  • Microsoft Internet Information Server 4.0

This article was previously published under Q304088
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

A Web site that is hosted on an Internet Information Server (IIS) or Internet Information Services (IIS) server behind a Load Balancing or Network Address Translation (NAT) device may redirect browsers to an incorrect IP address when you use relative paths in content that is hosted. This can result in several different error messages depending on what the malformed URL contains.

CAUSE

When IIS parses a relative URL in an HTML or Active Server Pages (ASP) page, it uses the incoming port and address to generate a fully qualified URL to send to the requesting browser. If a front end device changes the IP or address that is used to connect to the IIS server internally, it can cause the internal network names or IP addresses to be used to generate fully qualified URLs. If this occurs, a malformed URL can be sent back to the requesting browser and can cause the link to be invalid from the client computer.

RESOLUTION

If this problem occurs, use fully qualified path names in content that is hosted behind a Load Balancing or NAT device.

Modification Type:MinorLast Reviewed:6/22/2005
Keywords:kbpending kbprb KB304088