Let's Encrypt and FortiGate

[Alby23]

Do u know if it's possible to use a Let's Encrypt-generated certificate into the FortiGate for the VPN Portal?

[mhe · Accepted solution]

No, I don't think that you can use LE certificates. You need their app on the device to use it. But you can use startssl

[emnoc · Accepted solution]

Mhe has it right.

Natively the answer is NO, but you have ways around this. Use a linux bistro build a csr/priv-key sign the csr and then export , re-import it in fortigate.

Yes any x509 compatible certificate will work in  a fortigate but the native means of "let's encrypt" make it not a 1 2 3  easy-do  method.

[NeilG · Accepted solution]

The problem with the manual import is that you will be running the manual process probably 5 times a year as letsencrypt issuance is 90days.

"Our certificates are valid for 90 days. You can read about why here."

https://letsencrypt.org/docs/faq/

-N

[jtfinley · Accepted solution]

So here's what I did using a raspberry pi, but can be easily used on other platforms...

[ol]

Install letsencrypt (https://letsencrypt.org/getting-started) on a box with tcp/80, tcp/443 open. (Raspberry Pi - used CertBot)

Temporarily point a DNS A or CNAME record of your (Raspberry Pi Box) SSL VPN at the box you're going to run letsencrypt on.

Once it pulls dependencies - Run letsencrypt using example below.

[ol]

 ./certbot-auto certonly --standalone -d vpn.yoursite.com -d [[/ol]

Change DNS records if required by pointing your DNS A record back at your SSL VPN IP

Grab your pems from /etc/letsencrypt/live/vpn.yoursite.com (cert.pem & privkey.pem) [/ol]

FortiGate:

[ol]

System -> Config -> Certificates -> Import -> Local Certificate. Set type to Certificate. For certificate choose cert.pem and for key choose privkey.pem

VPN -> SSL -> Settings. Change Server Certificate.

Repeat process every 90 days

Setup CronJob to renew it.[/ol]

[emnoc]

Yes that true , it made it a lot easier with certificate and applying the  certs for multiple objects.

Ken Felix

[absmith]

So I have the functionality in the script to upload the certificate and private-key however, Fortigate functionality doesn't let you overwrite the current certificate, and even if it did you would have to remove and then re-add ssl functionality to the specific service if you are overwriting the certificate.

Since this is the case, I'm going to also have to write functionality to change the certificates of rules, VPN portals, Virtual servers, either into the same script or into a separate script.  Let me know if anyone is interested so far.

[cookem]

sounds cool....can I get a copy of what you have so far?

[Keith_Nelson]

adam_smith@sundance.org wrote:

So I have the functionality in the script to upload the certificate and private-key however, Fortigate functionality doesn't let you overwrite the current certificate, and even if it did you would have to remove and then re-add ssl functionality to the specific service if you are overwriting the certificate.

Since this is the case, I'm going to also have to write functionality to change the certificates of rules, VPN portals, Virtual servers, either into the same script or into a separate script.  Let me know if anyone is interested so far.

I would be interested in the script.

I have been trying to figure this out for awhile but im not much of a scripter.

You would think this would be an API they would have given all the rage of DevOPs these days.

[emnoc]

1: upload the  new cert and then change the useage to the new cert 

2: delete the old certificate

[absmith]

there doesn't seem to be a way for me to put the file here but I am planning to put it up on github so that as it evolves people can get the latest versions.  I also am planning on releasing it with an apache v2 license, so don't worry about changing it for your own purposes and any contributions/suggestions would help.  Sorry for taking so long to post it.  I was trying to add a config file functionality that is present in the code but is not fully working yet.  However all the command line options all work.  This is a python script and relies on  fortiosapi so you will have to use that.  It was written with python3 in mind so it may or may not be reverse compatible with python2.  I actually think that it won't be reverse compatible because of the configuration file library I used changed the syntax for the library name when it moved over to python3.  With that in mind here is what I have currently.

I am also planning on making it compatible with pypi so you can just do a pip install, but that isn't all in place yet.  I'll post the link as soon as I get it on github.

[absmith]

Here is the github-repo for the current version,  it's still a bit early but it does work.  The --help feature should give you all the parameters required.  I'm trying to write it to have a config file as well so that you don't need to write the whole command every time, the beginning framework is there for this in the script but is not fully tested yet so I suggest using the cli commands.  Also this works with either password or API-Key authentication.  Let me know if things aren't working for you.

https://github.com/absmith82/fortitools

[lubyou]

Fortinet could just add support for LetsEncrypt into FortiOS, the ACME protocol is open source and anybody can write a client for it.

Apart from that, Fortinet already uses python in FortiOS, they could use certbot...

[absmith]

I agree that would be ideal, however, that isn't currently the case, and as far as I can tell fortios doesn't allow you to access the python shell/ecosystem so in the meantime we have to work with the tools they allow us to.

[nbctcp]

https://www.loggly.com/blog/benchmarking-5-popular-load-balancers-nginx-haproxy-envoy-traefik-and-al...

comparing traefik with others I never try your idea. I believe it will work with GUI

but how about SSL VPN. Have you tried? I like your idea because I can use cron to renew every 90d

* */8 * * * certbot renew --post-hook "systemctl reload nginx"

I don't know which way is better and easier. 1. using reverse proxy 2. create a script like emnoc said 3. update cert using this method https://kb.fortinet.com/kb/documentLink.do?externalID=FD35074 4. [link]https://github.com/absmith82/fortitools[/link]

tq

peter.wickenberg wrote:

I solved it by setting up a reverse proxy using Traefik and Letsencrypt to give me access to mgmt and SSL VPN through the proxy, that way I get automatically updated certificates for both services by bouncing it on the inside, can't say it's affecting performance either.