diff --git a/server.py b/server.py
index 89a0f7f..c62c8b5 100644
--- a/server.py
+++ b/server.py
@@ -130,7 +130,7 @@ class DnsProxy(Handler):
         try:
             self.sock.send(self.request)
         except socket.error, e:
-            if e.args[0] in [errno.ECONNREFUSED, errno.EHOSTUNREACH]:
+            if e.args[0] in ssnet.NET_ERRS:
                 # might have been spurious; try again.
                 # Note: these errors sometimes are reported by recv(),
                 # and sometimes by send().  We have to catch both.
@@ -145,7 +145,7 @@ class DnsProxy(Handler):
         try:
             data = self.sock.recv(4096)
         except socket.error, e:
-            if e.args[0] in [errno.ECONNREFUSED, errno.EHOSTUNREACH]:
+            if e.args[0] in ssnet.NET_ERRS:
                 # might have been spurious; try again.
                 # Note: these errors sometimes are reported by recv(),
                 # and sometimes by send().  We have to catch both.
diff --git a/ssnet.py b/ssnet.py
index a987562..b6d73c2 100644
--- a/ssnet.py
+++ b/ssnet.py
@@ -40,7 +40,11 @@ cmd_to_name = {
     CMD_DNS_REQ: 'DNS_REQ',
     CMD_DNS_RESPONSE: 'DNS_RESPONSE',
 }
-    
+
+
+NET_ERRS = [errno.ECONNREFUSED, errno.ETIMEDOUT,
+            errno.EHOSTUNREACH, errno.ENETUNREACH,
+            errno.EHOSTDOWN, errno.ENETDOWN]
 
 
 def _add(l, elem):
@@ -151,9 +155,7 @@ class SockWrapper:
             elif e.args[0] == errno.EISCONN:
                 # connected successfully (BSD)
                 self.connect_to = None
-            elif e.args[0] in [errno.ECONNREFUSED, errno.ETIMEDOUT,
-                               errno.EHOSTUNREACH, errno.ENETUNREACH,
-                               errno.EACCES, errno.EPERM]:
+            elif e.args[0] in NET_ERRS + [errno.EACCES, errno.EPERM]:
                 # a "normal" kind of error
                 self.connect_to = None
                 self.seterr(e)