diff --git a/src/kex.rs b/src/kex.rs
index 7ee639b0f16ce2803e7519db3597dd5b3a69c0bc..c4a456546c885215bfa5a4c1fab619a5dd54e6b2 100644
--- a/src/kex.rs
+++ b/src/kex.rs
@@ -32,7 +32,7 @@ use pretty_hex::PrettyHex;
 
 // TODO this will be configurable.
 const fixed_options_kex: &[&'static str] =
-    &[SSH_NAME_CURVE25519, SSH_NAME_CURVE25519_LIBSSH];
+    &[SSH_NAME_CURVE25519, SSH_NAME_CURVE25519_LIBSSH, SSH_NAME_KEXGUESS2];
 
 /// Options that can't be negotiated
 const marker_only_kexs: &[&'static str] =