diff --git a/src/domain/tls/certificate.rs b/src/domain/tls/certificate.rs
index 24071b3..d3003e4 100644
--- a/src/domain/tls/certificate.rs
+++ b/src/domain/tls/certificate.rs
@@ -31,6 +31,10 @@ impl Certificate {
         };
 
         let mut builder = X509::builder().expect("initializing x509 builder");
+        builder
+            .set_version(2) // version number is 0-indexed, so this is version 3
+            .or_unexpected_while("setting version")?;
+
         builder
             .set_subject_name(&name)
             .or_unexpected_while("setting subject name")?;