Today’s tutorial shows how quickly and easily a Docker port scanner can be created. With the knowledge you can then create additional Docker applications.

Preparation

# prepare knocker project (local)
$ mkdir ~/Projects/Knocker && cd ~/Projects/Knocker

# create Dockerfile (local)
$ vim Dockerfile

# create KnockerVM (local)
$ docker-machine create -d virtualbox KnockerVM

# pointing shell to KnockerVM (local)
$ eval $(docker-machine env KnockerVM)

# copy Dockerfile into KnockerVM (local)
$ docker-machine scp ~/Projects/Knocker/Dockerfile KnockerVM:Dockerfile

# SSH into KnockerVM (local)
$ docker-machine ssh KnockerVM

Dockerfile

FROM alpine

# install needed packages
RUN apk --update add wget build-base gcc abuild binutils binutils-doc gcc-doc

# download and unzip
RUN wget http://prdownloads.sourceforge.net/knocker/knocker-0.7.1.tar.gz
RUN tar -zxvf knocker-0.7.1.tar.gz && rm -f knocker-0.7.1.tar.gz

# configure, install and clean up
WORKDIR /knocker-0.7.1
RUN ./configure \
    && make install \
    && make clean

# create mountable directory
RUN mkdir /results
VOLUME /results
WORKDIR /results

# remove packages
RUN apk del wget build-base gcc abuild binutils binutils-doc gcc-doc \
    && rm -fr /knocker-0.7.1

ENTRYPOINT ["knocker"]

Usage

# build Docker image (KnockerVM)
$ docker build -t alpine/knocker .

# run Knocker help (KnockerVM)
$ docker run -ti --rm alpine/knocker --help

# run simple port scan (KnockerVM)
$ docker run -ti --rm alpine/knocker -H 192.168.192.1 -SP 1 -EP 10

# run port scan with (KnockerVM)
$ docker run -ti --rm -v /home/docker:/results alpine/knocker -H 192.168.192.1 -SP 80 -EP 90 -lf /results/report

# read report (KnockerVM)
$ cat report

Feel free to edit and/or expand! Knocker self can be found here.