diff --git a/sshuttle/cmdline.py b/sshuttle/cmdline.py
index 11d6796..a32c6e7 100644
--- a/sshuttle/cmdline.py
+++ b/sshuttle/cmdline.py
@@ -9,7 +9,7 @@ import sshuttle.firewall as firewall
 import sshuttle.hostwatch as hostwatch
 import sshuttle.ssyslog as ssyslog
 from sshuttle.options import parser, parse_ipport
-from sshuttle.helpers import family_ip_tuple, log, Fatal
+from sshuttle.helpers import family_ip_tuple, log, Fatal, start_stdout_stderr_flush_thread
 from sshuttle.sudoers import sudoers
 
 
diff --git a/sshuttle/hostwatch.py b/sshuttle/hostwatch.py
index 35ab2cc..1884165 100644
--- a/sshuttle/hostwatch.py
+++ b/sshuttle/hostwatch.py
@@ -18,6 +18,8 @@ CACHEFILE = os.path.expanduser('~/.sshuttle.hosts')
 # Have we already failed to write CACHEFILE?
 CACHE_WRITE_FAILED = False
 
+SHOULD_WRITE_CACHE = False
+
 hostnames = {}
 queue = {}
 try:
@@ -81,6 +83,11 @@ def read_host_cache():
             ip = re.sub(r'[^0-9.]', '', ip).strip()
             if name and ip:
                 found_host(name, ip)
+    f.close()
+    global SHOULD_WRITE_CACHE
+    if SHOULD_WRITE_CACHE:
+        write_host_cache()
+        SHOULD_WRITE_CACHE = False
 
 
 def found_host(name, ip):
@@ -97,12 +104,13 @@ def found_host(name, ip):
     if hostname != name:
         found_host(hostname, ip)
 
+    global SHOULD_WRITE_CACHE
     oldip = hostnames.get(name)
     if oldip != ip:
         hostnames[name] = ip
         debug1('Found: %s: %s' % (name, ip))
         sys.stdout.write('%s,%s\n' % (name, ip))
-        write_host_cache()
+        SHOULD_WRITE_CACHE = True
 
 
 def _check_etc_hosts():
diff --git a/tests/client/test_helpers.py b/tests/client/test_helpers.py
index bfbb145..794c284 100644
--- a/tests/client/test_helpers.py
+++ b/tests/client/test_helpers.py
@@ -2,6 +2,7 @@ import io
 import socket
 from socket import AF_INET, AF_INET6
 import errno
+import time
 
 from unittest.mock import patch, call
 import sshuttle.helpers