diff --git a/docs/LagoInitFile.rst b/docs/LagoInitFile.rst
index 6ee9c2ed..af3c49e1 100644
--- a/docs/LagoInitFile.rst
+++ b/docs/LagoInitFile.rst
@@ -164,12 +164,15 @@ domains
 
 nets
 ----
-``<name>``: The name of the network.
+``<name>``: The name of the network, should be an alphanumeric string.
+            Currently we do not enforce that it is only alphanumeric,
+            but we might do so in the future.
 
     type(string)
         Type of the network. May be `nat` or `bridge`.
 
 
+
 .. _Templates: Templates.html
 .. _`virt-customize`: http://libguestfs.org/virt-customize.1.html
 .. _lago-ost-plugin: https://github.com/lago-project/lago-ost-plugin/blob/master/setup.cfg
diff --git a/lago/virt.py b/lago/virt.py
index 20a6029b..dc3e4ded 100644
--- a/lago/virt.py
+++ b/lago/virt.py
@@ -23,7 +23,7 @@
 import logging
 import os
 import uuid
-
+import re
 import yaml
 
 from lago import log_utils, plugins, utils
@@ -126,10 +126,15 @@ def prefixed_name(self, unprefixed_name, max_length=0):
                 will adapt the given name and the length of the uuid ot fit it
 
         Returns:
-            str: prefixed identifier for the given unprefixed name
+            str: prefixed identifier for the given unprefixed name, with all
+                none alphanumeric characters in the unprefixed name replaced
+                with a 'L'
         """
+
+        not_alphanumeric = re.compile(r'[^a-zA-Z0-9]')
+        unprefixed_name = not_alphanumeric.sub('L', unprefixed_name)
         if max_length == 0:
-            prefixed_name = '%s-%s' % (self.uuid[:8], unprefixed_name)
+            prefixed_name = '%s%s' % (self.uuid[:8], unprefixed_name)
         else:
             if max_length < 6:
                 raise RuntimeError(
@@ -147,8 +152,8 @@ def prefixed_name(self, unprefixed_name, max_length=0):
                 hashed_name = hashlib.sha1(unprefixed_name).hexdigest()
                 unprefixed_name = hashed_name[:name_max_length]
 
-            prefixed_name = '%s-%s' % (_uuid, unprefixed_name)
-
+            prefixed_name = '%s%s' % (_uuid, unprefixed_name)
+        LOGGER.debug('prefixed_name %s', prefixed_name)
         return prefixed_name
 
     def virt_path(self, *args):