How to setup Ngrok with a self-signed SSL cert

ngrok-selfhosting-setup.md

Intro

The plan is to create a pair of executables (ngrok and ngrokd) that are connected with a self-signed SSL cert. Since the client and server executables are paired, you won't be able to use any other ngrok to connect to this ngrokd, and vice versa.

DNS

Add two DNS records: one for the base domain and one for the wildcard domain. For example, if your base domain is domain.com, you'll need a record for that and for *.domain.com.

Different Operating Systems

If the OS on which you'll be compiling ngrok (that's the server section below) is different than the OS on which you'll be running the client, then you will need to set the GOOS and GOARCH env variables. I run Linux everywhere, so I don't know how to do that. Please Google it or see the discussion here. If you know how to do this and want to add GOOS/GOARCH instructions here, please let me know.

On Server

MAKE SURE YOU SET NGROK_DOMAIN BELOW. Set it to the base domain, not the wildcard domain.

NGROK_DOMAIN="my.domain.com"
git clone https://github.com/inconshreveable/ngrok.git
cd ngrok

openssl genrsa -out rootCA.key 2048
openssl req -x509 -new -nodes -key rootCA.key -subj "/CN=$NGROK_DOMAIN" -days 5000 -out rootCA.pem
openssl genrsa -out device.key 2048
openssl req -new -key device.key -subj "/CN=$NGROK_DOMAIN" -out device.csr
openssl x509 -req -in device.csr -CA rootCA.pem -CAkey rootCA.key -CAcreateserial -out device.crt -days 5000

cp rootCA.pem assets/client/tls/ngrokroot.crt
# make clean
make release-server release-client

Copy bin/ngrok to whatever computer you want to connect from. Then start the server:

bin/ngrokd -tlsKey=device.key -tlsCrt=device.crt -domain="$NGROK_DOMAIN" -httpAddr=":8000" -httpsAddr=":8001"

On Client

MAKE SURE YOU SET NGROK_DOMAIN BELOW. Set it to the base domain, not the wildcard domain.

NGROK_DOMAIN="my.domain.com"
echo -e "server_addr: $NGROK_DOMAIN:4443\ntrust_host_root_certs: false" > ngrok-config
./ngrok -config=ngrok-config 80

Or for SSH forwarding: ./ngrok -config=ngrok-config --proto=tcp 22

Thank you so much. I've created one as ngrok.com is slow in China.

Hey there,

I have question about *.host.com certificate. Why when I issue cert on *.host.com and compile code with same certificate ngrok client can't connect with server?
Why do I need *.host.com? Well to use https. I have been only able to set up tunnel with certificate issued on host.com. When after setting up a tunnel I type http://subdomain.host.com it works fine, but when I go to https://subdomain.host.com It doesn't work - it complains that certificate is not issued on subdomain.host.com but on host.com.
Also why if I create CA with host.com and then create server.crt with *.host.com it also doesn't work?
Can anyone please explain me how ngrok is using both those certs (root.pem and server.key, server.crt)

Thanks

It might be a good idea to also edit defaultServerAddr in src/ngrok/client/model.go to $NGROK_DOMAIN:4443 (Don't put $NGROK_DOMAIN literally in the file. Put your domain there). Then everything will work for your users without them needing a config file.

Also you can easily cross-compile using GOPATH=$(pwd) gox -tags 'release' ngrok/main/ngrok (to install gox: go get github.com/mitchellh/gox), as long as you've done everything lined out in the gist above, including make release-client.

Just FYI, if you use server on linux and client on OS X, it will be very easy to use golang docker image to make a cross compile.

docker pull golang:1.4.3-cross
cd ngrok
docker run --rm  -v `pwd`:`pwd` -w `pwd` golang:1.4.3-cross make release-server
docker run --rm  -v `pwd`:`pwd` -w `pwd` -e GOOS=darwin -e GOARCH=amd64 golang:1.4.3-cross make release-client

Then in the bin directory, you can find ngrokd and darwin_amd64/ngrok.

🍻 😆

In my case, I needed a server binary for an Ubuntu droplet on Digital Ocean, and client binaries for a Macbook Pro and Raspberry Pi. So I did the following:

GOOS="linux" GOARCH="amd64" make release-server
GOOS="darwin" GOARCH="amd64" make release-client
GOOS="linux" GOARCH="arm" make release-client

All possible GOOS / GOARCH values are documented here.

Thanks a lot! It works well!

I just want to point out a thing for the people that stumble upon this article (very helpful btw, thank you). It is really important that you compile you server and client application with the certificate that your going to use already copied into the assets/client/tls/ folder. Otherwise you'll get the Failed to read message: remote error: bad certificate error.

Hi @danielmorandini , I'm getting the error you mentioned. Don't really understand your suggestion on how to fix it, do you mind to explain more? Thanks!

@danielmorandini , @h4ck4life,

same problem here. Tried to rebuild client with custom root CA but its not working, still getting errors of invalid certificates..

I've tried everything suggested here. Just can't seem to get it working.. bad certificate error.

I have more general questions. Preface; Once the binaries are compiled using "make release-server release-client", they show up in the "bin" sub directory (along with another file in there called "go-bindata").

When starting the server as described in this forum, does the "device.key" and "device.crt" need to be in the "bin" directory as well (same directory as "ngrokd")?

When starting the client (using the "ngrok-config"), does the "ngrokroot.crt need to be in the same directory as "ngrok"?

Or, am I totally confused?

Any help is greatly appreciated.

Make sure to do cp rootCA.pem assets/client/tls/ngrokroot.crt and rootCA.pem is your own certificate.

@przano

When starting the server as described in this forum, does the "device.key" and "device.crt" need to be in the "bin" directory as well (same directory as "ngrokd")?

Yes.

For simplicity, you can build a ngrokd image with docker:

Dockerfile

FROM alpine:latest

WORKDIR /opt
ADD ngrokd device.key device.crt ./

EXPOSE 80
EXPOSE 443
EXPOSE 4443

ENTRYPOINT ["./ngrokd","-tlsKey","device.key","-tlsCrt","device.crt","-domain","yourdomain.com"]

Build and push the image

env GOOS=linux GOARCH=amd64 make release-server
cp bin/ngrokd
docker build . -t yourname/ngrok:latest
docker push yourname/ngrok:latest

Run on server

On the server, just execute docker run -d --restart=always -p 80:80 -p 443:443 -p 4443:4443 yourname/ngrok:latest.

When starting the client (using the "ngrok-config"), does the "ngrokroot.crt need to be in the same directory as "ngrok"?

No.

Make sure you have put the crt in assets/client/tls/ before make release-client. It will be packaged into the binary.

Thanks for response @goofansu. It appears to be working now.

I execute the same command. But I always meet:

[16:12:42 CST 2018/11/17] [INFO] (ngrok/log.(*PrefixLogger).Info:83) [tun:201b1722] New connection from 113.87.12.25:26278
[16:12:42 CST 2018/11/17] [DEBG] (ngrok/log.(*PrefixLogger).Debug:79) [tun:201b1722] Waiting to read message
[16:12:42 CST 2018/11/17] [WARN] (ngrok/log.(*PrefixLogger).Warn:87) [tun:201b1722] Failed to read message: remote error: tls: bad certificate
[16:12:42 CST 2018/11/17] [DEBG] (ngrok/log.(*PrefixLogger).Debug:79) [tun:201b1722] Closing

What's the problem?
Thank you.

Also why if I create CA with host.com and then create server.crt with *.host.com it also doesn't work?Can anyone please explain me how ngrok is using both those certs (root.pem and server.key, server.crt)

@damtur I just have the same problems !!!!

It might be a good idea to also edit defaultServerAddr in src/ngrok/client/model.go to $NGROK_DOMAIN:4443 (Don't put $NGROK_DOMAIN literally in the file. Put your domain there). Then everything will work for your users without them needing a config file.

Also you can easily cross-compile using GOPATH=$(pwd) gox -tags 'release' ngrok/main/ngrok (to install gox: go get github.com/mitchellh/gox), as long as you've done everything lined out in the gist above, including make release-client.

Cant we put defaultServerAddr in src/ngrok/client/model.go to $NGROK_DOMAIN:443 and not 4443?

I encounter the "bad certificate", too.
The error message from client shows

[01:53:34 CST 2021/02/13] [EROR] (ngrok/log.Error:120) control recovering from failure x509: certificate relies on legacy Common Name field, use SANs or temporarily enable Common Name matching with GODEBUG=x509ignoreCN=0

After searching, seems like ignoreCN are relative to go 1.15,
I tried export GODEBUG=x509 ignoreCN=0 and export GODEBUG=x509ignoreCN=0 with no luck.

Finally, I use gvm to install go 1.14 and rebuild, and it works now.

gvm install go1.14.15
gvm use go1.14
make release-server release-client

I encounter the "bad certificate", too.
The error message from client shows

[01:53:34 CST 2021/02/13] [EROR] (ngrok/log.Error:120) control recovering from failure x509: certificate relies on legacy Common Name field, use SANs or temporarily enable Common Name matching with GODEBUG=x509ignoreCN=0

After searching, seems like ignoreCN are relative to go 1.15,
I tried export GODEBUG=x509 ignoreCN=0 and export GODEBUG=x509ignoreCN=0 with no luck.

Finally, I use gvm to install go 1.14 and rebuild, and it works now.

gvm install go1.14.15
gvm use go1.14
make release-server release-client

You save my life...
I tried to install on ec2, and by default yum install golang installed go1.15

I found a similar tool with more features, it's frp

It support udp port forwarding, range port forwarding, and forwarding specific ip on local (192.168.x.x for example) rather than localhost (127.0.0.1).

Just leave a note in case someone has similar needs.

Thankyou this helped a lot

Hello Guys, i am getting this error

Please help me, I am new to this.

I encounter the "bad certificate", too. The error message from client shows

[01:53:34 CST 2021/02/13] [EROR] (ngrok/log.Error:120) control recovering from failure x509: certificate relies on legacy Common Name field, use SANs or temporarily enable Common Name matching with GODEBUG=x509ignoreCN=0

After searching, seems like ignoreCN are relative to go 1.15, I tried export GODEBUG=x509 ignoreCN=0 and export GODEBUG=x509ignoreCN=0 with no luck.

Finally, I use gvm to install go 1.14 and rebuild, and it works now.

gvm install go1.14.15
gvm use go1.14
make release-server release-client

Well done!
Thanks man!

make: *** No rule to make target 'release-server'. Stop.
hi, does anyone know how to solve this problem?