1 files changed, 2 insertions, 2 deletions

diff --git a/src/mailman/mta/postfix.py b/src/mailman/mta/postfix.py
index 56ede5b45..df5419515 100644
--- a/src/mailman/mta/postfix.py
+++ b/src/mailman/mta/postfix.py
@@ -126,13 +126,13 @@ class LMTP:
                 # len('-subscribe') + '@'.
                 longest = len(list_name + domain) + 10
                 print >> fp, """\
-{0}@{1:{3}}lmtp:{2.mta.lmtp_host}:{2.mta.lmtp_port}""".format(
+{0}@{1:{3}}lmtp:[{2.mta.lmtp_host}]:{2.mta.lmtp_port}""".format(
                     list_name, domain, config,
                     # Add 1 because the bare list name has no dash.
                     longest + 1)
             for destination in SUBDESTINATIONS:
                 print >> fp, """\
-{0}-{1}@{2:{4}}lmtp:{3.mta.lmtp_host}:{3.mta.lmtp_port}""".format(
+{0}-{1}@{2:{4}}lmtp:[{3.mta.lmtp_host}]:{3.mta.lmtp_port}""".format(
                     list_name, destination, domain, config,
                     longest - len(destination))
             print >> fp