diff --git a/pkgs/clan-cli/clan_cli/ssh/__init__.py b/pkgs/clan-cli/clan_cli/ssh/__init__.py
index 27d0a8c47..3ac8ec17b 100644
--- a/pkgs/clan-cli/clan_cli/ssh/__init__.py
+++ b/pkgs/clan-cli/clan_cli/ssh/__init__.py
@@ -845,6 +845,10 @@ def parse_deployment_address(
         meta = {}
     parts = host.split("@")
     user: str | None = None
+    # count the number of : in the hostname
+    if host.count(":") > 1 and not host.startswith("["):
+        msg = f"Invalid hostname: {host}. IPv6 addresses must be enclosed in brackets , e.g. [::1]"
+        raise ClanError(msg)
     if len(parts) > 1:
         user = parts[0]
         hostname = parts[1]
diff --git a/pkgs/clan-cli/tests/test_ssh_remote.py b/pkgs/clan-cli/tests/test_ssh_remote.py
index 04dd2e3fd..3516c1476 100644
--- a/pkgs/clan-cli/tests/test_ssh_remote.py
+++ b/pkgs/clan-cli/tests/test_ssh_remote.py
@@ -1,5 +1,7 @@
 import subprocess
 
+import pytest
+from clan_cli.errors import ClanError
 from clan_cli.ssh import Host, HostGroup, HostKeyCheck, parse_deployment_address
 
 
@@ -11,6 +13,10 @@ def test_parse_ipv6() -> None:
     assert host.host == "fe80::1%eth0"
     assert host.port is None
 
+    with pytest.raises(ClanError):
+        # We instruct the user to use brackets for IPv6 addresses
+        host = parse_deployment_address("foo", "fe80::1%eth0", HostKeyCheck.STRICT)
+
 
 def test_run(host_group: HostGroup) -> None:
     proc = host_group.run("echo hello", stdout=subprocess.PIPE)