Firefox Proxy to Docker Fiddler refusing connection - firefox

Question

Running docker-fiddler container on Ubuntu-14.04 host. Container brings up fiddler and redirects GUI to host, but proxy fails. Docker ver 1.11.1,
Firefox displays either "The connection was reset" or "The proxy server is refusing connections" depending on setups shown below.
Question:
What are the correct Firefox proxy settings, http and ssl?
What changes are need to docker run cmd line?
What changes are need for the Dockerfile?
Note: I am hitting an http url, not https
This configuration, localhost, assuming port fwd, FF Output: The connection was reset
Firefox proxy:
manual proxy
HTTP Proxy 127.0.0.1 Port 8888
SSL Proxy 127.0.0.1 Port 8888
This Configuration, using container ip, FF Output: The Proxy server is refusing connections
Firefox proxy:
manual proxy
HTTP Proxy 172.17.02 Port 8888
SSL Proxy 172.17.02 Port 8888
TL;DR
Docker Run:
docker run -d -p 8888:8888 -v /tmp/.X11-unix:/tmp/.X11-unix -e \
DISPLAY=$DISPLAY fiddler -h $HOSTNAME -v \
$HOME/.Xauthority:/home/$USER/.Xauthority
docker ps:
16a4f7531222 fiddler "mono /app/Fiddler.ex" 3 hours ago Up 3 hours 0.0.0.0:8888->8888/tcp cranky_pare
Dockerfile jwieringa/docker-fiddler , I added expose 8888, and User config to support bind mount X server
FROM debian:wheezy
RUN apt-get update \
&& apt-get install -y curl unzip \
&& rm -rf /var/lib/apt/lists/*
RUN apt-key adv --keyserver pgp.mit.edu --recv-keys 3FA7E0328081BFF6A14DA29AA6A19B38D3D831EF
RUN echo "deb http://download.mono-project.com/repo/debian wheezy/snapshots/3.12.0 main" > /etc/apt/sources.list.d/mono-xamarin.list \
&& apt-get update \
&& apt-get install -y mono-devel ca-certificates-mono fsharp mono-vbnc nuget \
&& rm -rf /var/lib/apt/lists/*
RUN cd /tmp && curl -O http://ericlawrence.com/dl/MonoFiddler-v4484.zip
RUN unzip /tmp/MonoFiddler-v4484.zip
## I added this for X11 Display of Fiddler GUI on linux Host
RUN groupadd -g <gid> <user>
RUN useradd -d /home/<user> -s /bin/bash -m <user> -u <uid> -g <gid>
USER <user>
ENV HOME /home/<user>
# I added this also
EXPOSE 8888
ENTRYPOINT ["mono", "/app/Fiddler.exe"]

Answer 1

1) The Host is considered a remote computer to docker-fiddler container
Fiddler > Tools > Fiddler Options > Connections > [x] Allow remote computers to connect
2) Fiddler requires a reset after changing this attribute, this closes the container. must add bind-mount volume to Dockerfile to maintain config
-v /tmp/docker-fiddler/.mono:/home/$USER/.mono
3) create /tmp/docker-fiddler/.mono on the host first and give it $USER permissions. Docker should do this for me but, I'm not sure how
4) Changed docker run to :
docker run -d -p 8888:8888 \
-v /tmp/.X11-unix:/tmp/.X11-unix \
-h $HOSTNAME \
-v $HOME/.Xauthority:/home/$USER/.Xauthority \
-v /tmp/docker-fiddler/.mono:/home/$USER/.mono \
-e DISPLAY=$DISPLAY fiddler
5) For debugging, change the first line above to add Debug (-D) and remove daemon (-d), doing this was key to finding the missing libs
docker -D run -p 8888:8888
6) There were several libs missing, the last one was gsettings-desktop-schema which contains/brings in the gnome proxy schema. This is used by fiddler, until this was in place the "AllowRemote" config setting was not being stored
.mono/registry/CurrentUser/software/telerik/fiddler/values.xml:<value name="AllowRemote"
7) Several changes to Dockerfile, including using ubuntu, creates a very large image, might be able to backout libglib2.0-bin libcanberra-gtk-module:
FROM ubuntu:14.04
RUN apt-get update \
&& apt-get install -y curl unzip libglib2.0-bin libcanberra-gtk-module gsettings-desktop-schemas \
&& rm -f /etc/apt/sources.list.d/mono-xamarin* \
&& rm -rf /var/lib/apt/lists/*
RUN apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys 3FA7E0328081BFF6A14DA29AA6A19B38D3D831EF
RUN echo "deb http://download.mono-project.com/repo/debian wheezy main" > /etc/apt/sources.list.d/mono-xamarin.list \
&& apt-get update \
&& apt-get install -y mono-complete ca-certificates-mono fsharp mono-vbnc nuget \
&& rm -rf /var/lib/apt/lists/*
RUN cd /tmp && curl -O http://ericlawrence.com/dl/MonoFiddler-v4484.zip
RUN unzip /tmp/MonoFiddler-v4484.zip
RUN groupadd -g 1000 <USER>
RUN useradd -d /home/<USER> -s /bin/bash \
-m <USER> -u <UID> -g <GID>
USER <user>
ENV HOME /home/<USER>
EXPOSE 8888
ENTRYPOINT ["mono", "/app/Fiddler.exe"]
8) Firefox Proxy, - did not address HTTPS/SSL
FF > edit > preferences > Advanced > settings
manual proxy
HTTP Proxy <container-ip> Port 8888
SSL Proxy <left this blank>
see: Install Mono on Linux
see: Docker In Practice, Miell/Sayers - CH4 Tech 26 Running GUIs, X11