PRB: Issues when a NAT router or load balancer is used between browsing users and WebMarshal

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This article applies to:

  • WebMarshal


Why are users seeing a large number of abort pages?


This problem can occur when another proxy device within the local network is configured to use a single credential to forward requests through WebMarshal or when IP authentication is used in a NAT (network address translation) router or load balancer between WebMarshal and the browsing users. The traffic will be treated as being for a unique computer user. The single user will be used when applying browsing rules, evaluating quotas, or showing any file abort notifications triggered by the content analysis rules. This means it is not possible to do reporting on individual usage.

All traffic from the user will appear to come from the IP address of the NAT router or load balancer. By default, WebMarshal can only see that IP address and cannot tell that there are multiple computers. All of these computers will be seen by WebMarshal as a single computer user and browsing rules will be applied accordingly. Quotas will apply to all computers, not just a single computer. File abort notifications will be shown on all computers until acknowledged by any user. All reporting data is logged against a single computer user and therefore it is not possible to do reporting on individual usage.

If a NAT router or load balancer is be used two options are available.

  • In a NAT environment, configure user based authentication. The credentials passed through will be used to identify users.
  • In a load balancing environment, use the X-Forwarded-For based IP authentication ability present in WebMarshal 7.5.0 and above. See the related article linked below.


  • If neither user-based authentication nor X-Forwarded-For authentication is available with NAT or load balanced environments, WebMarshal cannot perform any user-based logging or control of browsing activity.
  • If the proxy server or NAT router is able to forward the original user authentication account with requests then the problem should not occur.
  • See the WebMarshal User Guide for supported installation scenarios.

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