Troubleshooting macOS Proxy Settings and Network Access

Environment

Product
Product Version	1.6.0 and above
---	---
Operating System	macOS

Description

In some corner cases, the Fiddler Everywhere client might not access the macOS network settings—for example, due to administrative restrictions, firewall settings, and so on. How can I manually test the access to the active network adapter and its proxy settings on macOS?

Solution

To handle the issue, first access the name of the active network adapter and then further troubleshoot the proxy settings.

Accessing the Active Network Adapter Name

The Fiddler Everywhere client will use the name of the active network adapter (for example, something like Wi-FI) to set the Fiddler proxy. You can get the name manually by creating and executing a Shell script:

1. Create a Shell file through your preferred IDE. For demonstration purposes, name this file as test.sh.

2. In the newly created test.sh file, copy and paste the following Shell script.

   services=$(networksetup -listnetworkserviceorder | sed '1d;/(\*)/,+2d;s/^([^)]*) \(.*\)$/\1FIDDLER_SEPARATOR/g;s/^.*Device: \([^)]*\))/\1\t/g;/^$/d' | sed 'N;s/\n//')
   
   while read line; do
       sname=$(echo "$line" | awk -F  "FIDDLER_SEPARATOR" '{print $1}')
       sdev=$(echo "$line" | awk -F  "FIDDLER_SEPARATOR" '{print $2}')
       if [ -n "$sdev" ]; then
           ifconfig "$sdev" 2>/dev/null | grep 'status: active' > /dev/null 2>&1
           rc="$?"
           if [ "$rc" -eq 0 ]; then
               currentservice="$sname"
               echo "$currentservice"
               break
           fi
       fi
   done <<< "$(echo "$services")"
   
   if ! [ -n "$currentservice" ]; then
       >&2 echo "Could not find active network service for which to check the proxy configuration"
       >&2 echo "$services"
       >&2 networksetup -listnetworkserviceorder
       exit 1
   fi
   
   
   networksetup -getproxyautodiscovery "$currentservice"
   networksetup -getautoproxyurl "$currentservice"
   networksetup -getproxybypassdomains "$currentservice"
   networksetup -getwebproxy "$currentservice"
   networksetup -getsecurewebproxy "$currentservice"
   networksetup -getsocksfirewallproxy "$currentservice"
   

3. Execute the test.sh through the terminal.

   sh <path-to-script>/test.sh
   

Once you can successfully run the above script, you can use its output to troubleshoot possible issues with the active network adapter discovery.

The output from the above commands will vary depending on the OS network settings that are in place. You can use the output to troubleshoot your OS network settings with and without the Fiddler Everywhere capturing mode. For example, when Fiddler Everywhere is properly set to capture traffic and the capturing mode is ON, the getsecurewebproxy option will return the Fiddler proxy. By default, the Fiddler proxy is 127.0.0.1:8866.

The following example demonstrates a sample output for the networksetup -getwebproxy <adapter-name> command when no proxy is set.

Enabled: No
Server:
Port: 0
Authenticated Proxy Enabled: 0

The following example demonstrates a sample output for the networksetup -getwebproxy <adapter-name> command when the Fiddler Everywhere proxy is successfully set.

Enabled: Yes
Server: 127.0.0.1
Port: 8866
Authenticated Proxy Enabled: 0

On some occasions, you might have more than one active network adapters. Use the command networksetup -listnetworkserviceorder to get the names of all active adapters and then use the adapter name to troubleshoot the Fiddler Everywhere proxy settings.