Certbot and Let's Encrypt Now Support IP Address Certificates(eff.org)
eff.org
Certbot and Let's Encrypt Now Support IP Address Certificates
https://www.eff.org/deeplinks/2026/03/certbot-and-lets-encrypt-now-support-ip-address-certificates
14 comments
As seen in the BND's attack on jabber.ru, some adversaries have no difficulty taking over your IP address. Will this be a new threat vector?
> Will this be a new threat vector?
IMO no, because if they could take over your IP address they could already obtain a domain-validated certificate which is arguably a lot more valuable than an IP address certificate.
IMO no, because if they could take over your IP address they could already obtain a domain-validated certificate which is arguably a lot more valuable than an IP address certificate.
If an attacker manages to gain ownership of an IP address, and gets a Let's Encrypt certificate for that IP address, the certificate will show up in Certificate Transparency logs. In that way, if people are watching, the attack will become visible fairly quickly.
They should at least restricted it to IPv6. Here it will be a kill for everyone using mobile network and 5g hotspots.
Can you receive inbound connections on your hotspot?
At least in France and I think in a lot of other countries, you still get a dedicated IP for your connection, so yes you could receive inbound traffic.
Just the IP will most of the time be dynamic, and you might have your IP changing regularly.
Just the IP will most of the time be dynamic, and you might have your IP changing regularly.
When will they let me generate certificates for IMAP and SMTP?
They never stopped supporting it, to my knowledge. I first started using their certs for my IMAP and SMTP servers 10ish years ago, at least.
If you use HTTP-01 challenge method you require an HTTP server on the host.
If you don't want an HTTP server on your imap/smtp server you need to use the DNS-01 challenge method.
If you use HTTP-01 challenge method you require an HTTP server on the host.
If you don't want an HTTP server on your imap/smtp server you need to use the DNS-01 challenge method.
And what if I want to run DNS and http on separate servers than my mail server?
DNS-01 validation has nothing to do with where your DNS is hosted, all it takes is being able to create a DNS record to prove control over the zone.
The same thing everyone else does. Build automation, use configuration management, use cert manager or other similar solutions.
Update: Had less time to post than I realized, hence the terse reply.
Meant to say those solutions are in addition to Lets Encrypt. An X509 certificate is an X509 certificate, regardless if its for https, imaps, or smtps. If you're distributing your stuff across multiple hosts or containers, then it makes sense to use some sort of automation, configuration management, or certificate management/distribution system.
Meant to say those solutions are in addition to Lets Encrypt. An X509 certificate is an X509 certificate, regardless if its for https, imaps, or smtps. If you're distributing your stuff across multiple hosts or containers, then it makes sense to use some sort of automation, configuration management, or certificate management/distribution system.
Nice. I've been using lego for this the past few weeks.
Related 6-Day and IP Address Certificates Are Generally Available (506 points, 2 months ago, 281 comments) https://news.ycombinator.com/item?id=46647491