snowflake/probetest

Table of Contents

• Overview
• Running your own

This is code for a remote probe test component of Snowflake.

Overview

This is a probe test server to allow proxies to test their compatability with Snowflake. Right now the only type of test implemented is a compatability check for clients with symmetric NATs.

Running your own

The server uses TLS by default. There is a --disable-tls option for testing purposes, but you should use TLS in production.

To build the probe server, run go build

Or alternatively:

cd .. # switch to the repo root directory or $(git rev-parse --show-toplevel)
docker build -t snowflake-probetest -f probetest/Dockerfile .

To deploy the probe server, first set the necessary env variables with

export HOSTNAMES=${YOUR HOSTNAMES}
export EMAIL=${YOUR EMAIL}

then run docker-compose up

Setting up a symmetric NAT configuration requires a few extra steps. After upping the docker container, run docker inspect snowflake-probetest to find the subnet used by the probetest container. Then run sudo iptables -L -t nat to find the POSTROUTING rules for the subnet. It should look something like this:

Chain POSTROUTING (policy ACCEPT)
target     prot opt source               destination
MASQUERADE  all  --  172.19.0.0/16        anywhere

to modify this rule, execute the command sudo iptables -t nat -R POSTROUTING $RULE_NUM -s 172.19.0.0/16 -j MASQUERADE --random where RULE_NUM is the numbered rule corresponding to your docker container's subnet masquerade rule. Afterwards, you should see the rule changed to be:

Chain POSTROUTING (policy ACCEPT)
target     prot opt source               destination
MASQUERADE  all  --  172.19.0.0/16        anywhere      random