Localhost Traffic Capturing with Fiddler Everywhere

Environment

Product Fiddler Everywhere
Product Version 1.0.0 and above

Description

Traffic sent to http://localhost or http://127.0.0.1 is not captured when using some browsers like Google Chrome or Firefox (when Fiddler Everywhere capturing mode is turned on).

Solution

There are two different solutions, both of which are resolving the described problem. The first one is to use the machine name instead of localhost, and the second one is to use one of the specially provided aliases in Fiddler Everywhere. Note that both the aliases and the machine name replacement will work when Fiddler Everywhere client capturing mode is ON.

Using Machine Name

Use the machine name as an alias for localhost or 127.0.0.1 loopback addresses.

For example, let's assume the machine name is myrootuserid Instead of using localhost like this:

http://localhost:8081/mytestpage.aspx

Use the machine name as follows:

http://myrootuserid:8081/mytestpage.aspx

Using Aliases

Use a special Fiddler allias ipv4.fiddler (for connections using Internet Protocol version 4) or ipv6.fiddler (for connections using Internet Protocol version 6) or localhost.fiddler to hit localhost in the Host header (IIS Express).

Instead of using localhost like this:

http://localhost:8081/mytestpage.aspx

Use the alias as follows (to hit localhost on IPv4 adapter):

http://ipv4.fiddler:8081/mytestpage.aspx

or (to hit localhost on IPv6 adapter)

http://ipv6.fiddler:8081/mytestpage.aspx

or (to hit localhost in the Host header - applicable for ISS Express)

http://ipv4.fiddler:8081/mytestpage.aspx

Filter Localhost Traffic

While using one of the above solutions to capture localhost requests, the traffic will be captured in the Live Traffic list, and as host name, the loopback address will be displayed (usually 127.0.0.1). To filter by the Host column so that only localhost traffic is displayed, you will need to enter the loopback address as host value and not the aliases used in the browsers.

Example Localhost filtering

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