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Let's Encrypt works on internal networks too. Fun fact: TLS doesn't require certificates, and some browsers even used to support HTTPS in these TLS modes many
by zurn 7y ago
Let's Encrypt works on internal networks too.
Fun fact: TLS doesn't require certificates, and some browsers even used to support HTTPS in these TLS modes many moons ago. See eg https://security.stackexchange.com/questions/23024/can-diffie-hellman-anonymous-be-used-as-a-cipher-for-ssl-for-one-way-certifiate#23025 https://security.stackexchange.com/questions/23024/can-diffi...
- BrandoElFollito 7y agoAh? That's good to know! How to set this up on a domain which is not connected to Internet? How is the check done?
- benoliver999 7y agoIt's not easy but iirc you can do it with a DNS-01 challenge, if your internal domain name is valid (doesn't have to resolve to anything though).
- BrandoElFollito 7y agoThe problem is that I also have domains which are completely internal, not known/resolvable outside
- cheschire 7y agoCould you run an internal CA server instead of self signing? At least then you reduce your attack surface if you’re compromised internally.
- BrandoElFollito 7y agoYes, this is what is being done today. My point was that HTTPS is (much) more complicated than bare HTTP and this is probably one of the reasons it is not taking over the web in a storm (though progress is undoubtedly there)
- tialaramex 7y agoThis is probably a bad idea and I'd recommend migrating off such names as a background task. Realistically you can't entirely deconflict these names. So you always have a risk of shadowing names from the public Internet. The public CAs spent years in denial over this (yes they used to sell publicly trusted certs for "private" names, this is now prohibited). Create internal.example.com and things get easier. To the extent security by obscurity is worth trying it's just as available this way (split horizon DNS etcetera)
- lixtra 7y ago> Realistically you can't entirely deconflict these names. So you always have a risk of shadowing names from the public Internet. It's totally save and legitimate for ycombinator to use secret.ycombinator.com on their intranet without telling anything about it to the outside internet.
- tialaramex 7y agoThose are names you own, and a CA will happily issue you certs for those names (but Let's Encrypt won't without a DNS record saying the name at least exists) The grandparent was, as I understand it, talking about names they don't own, for which you've no assurance somebody else won't own them (on the public Internet) tomorrow. This used to be very common, decades ago Microsoft even advised corporations to do it for their AD, but it's a bad idea.
- kuschku 7y agoWhat's with domains such as blubb.mysystem.local or foo.invalid? .invalid and .local are reserved domains and guaranteed to never be in use on the public internet - yet I can't get certificates for them
- zurn 7y agoIf you could get certificates for them, so could anyone else including your adversaries, since there is no system of ownership for them. It would be like issuing certs for https://192.168.1.1 https://192.168.1.1
- zurn 7y agoIt works over DNS. There is a lot written about it on the net, I don't have any specific recommended article.
- BrandoElFollito 7y agoI now how to do the check over DNS when the name is known outside - the problem is that I have my own internal domain not visible on Internet
- zurn 7y agoYou need a registered domain for this. It's a good idea for other reasons too.
- mook 7y agoLet's Encrypt only works on public domains that happen to not route externally. I can never (or at least, should never) get LE certificates for *.pikachu.local, but that's a perfectly valid hostname for a local machine.