diff --git a/.gitignore b/.gitignore
index 4449579..f81140d 100644
--- a/.gitignore
+++ b/.gitignore
@@ -20,3 +20,5 @@ rebar3.crashdump
 
 config/dev.config
 apps/epp_proxy/priv/test_backend_app/pidfile
+
+.DS_Store
diff --git a/Dockerfile b/Dockerfile
index 98ca2ce..2183d91 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -3,7 +3,7 @@ FROM debian:buster-slim
 SHELL ["/bin/bash", "-o", "pipefail", "-c"]
 COPY ./docker/apt/sources.list /etc/apt/
 
-RUN apt-get update && apt-get -t buster install -y -qq wget \
+RUN apt-get update && apt-get install -y -qq wget \
   && apt-get clean \
   && rm -rf /var/lib/apt/lists/*
 
@@ -31,6 +31,8 @@ RUN apt-get update && apt-get install -y \
   libssl1.1=* \
   perl-base=* \
   zlib1g-dev \
+  net-tools \
+  iproute2 \
   && apt-get clean \
   && rm -rf /var/lib/apt/lists/*
 
diff --git a/apps/epp_proxy/src/epp_tls_acceptor.erl b/apps/epp_proxy/src/epp_tls_acceptor.erl
index a3c0080..60168af 100644
--- a/apps/epp_proxy/src/epp_tls_acceptor.erl
+++ b/apps/epp_proxy/src/epp_tls_acceptor.erl
@@ -25,7 +25,7 @@ init(Port) ->
 		      {active, false}, {reuseaddr, true},
 		      {verify, verify_peer}, {depth, 1},
 		      {cacertfile, ca_cert_file()}, {certfile, cert_file()},
-		      {keyfile, key_file()}],
+		      {keyfile, key_file()}, inet6],
     Options = handle_crl_check_options(DefaultOptions),
     {ok, ListenSocket} = ssl:listen(Port, Options),
     gen_server:cast(self(), accept),
@@ -33,6 +33,7 @@ init(Port) ->
      #state{socket = ListenSocket, port = Port,
 	    options = Options}}.
 
+
 %% Acceptor has only one state that goes in a loop:
 %% 1. Listen for a connection from anyone.
 %% 2. Ask supervisor to return a worker.
diff --git a/config/sys.config b/config/sys.config
index c2f3ae4..e4ca7b9 100644
--- a/config/sys.config
+++ b/config/sys.config
@@ -18,7 +18,7 @@
                {epp_command_url, "https://registry.test/epp/command/"},
                {epp_error_url, "https://registry.test/epp/error/"},
                %% Path to root CA that should check the client certificates.
-               {cacertfile_path, "/opt/shared/ca/certs/ca.crt.pem"},
+               {cacertfile_path, "/opt/ca/certs/ca.crt.pem"},
                %% Path to server's certficate file.
                {certfile_path, "/opt/shared/ca/certs/cert.pem"},
 
diff --git a/config/vm.args b/config/vm.args
index 03aad75..2d2475b 100644
--- a/config/vm.args
+++ b/config/vm.args
@@ -4,3 +4,4 @@
 
 +K true
 +A30
+