diff --git a/tiramisu/option/__init__.py b/tiramisu/option/__init__.py
index 909f1e6..78a6734 100644
--- a/tiramisu/option/__init__.py
+++ b/tiramisu/option/__init__.py
@@ -5,12 +5,12 @@ from .masterslaves import MasterSlaves
 from .baseoption import submulti
 from .symlinkoption import SymLinkOption
 from .syndynoption import SynDynOption
-from .option import Option, RegexpOption
+from .option import Option
 from .choiceoption import ChoiceOption
 from .booloption import BoolOption
 from .intoption import IntOption
 from .floatoption import FloatOption
-from .stroption import StrOption, UnicodeOption
+from .stroption import StrOption, UnicodeOption, RegexpOption
 from .ipoption import IPOption
 from .portoption import PortOption
 from .networkoption import NetworkOption
diff --git a/tiramisu/option/domainnameoption.py b/tiramisu/option/domainnameoption.py
index 8854a46..83c3488 100644
--- a/tiramisu/option/domainnameoption.py
+++ b/tiramisu/option/domainnameoption.py
@@ -24,9 +24,10 @@ from IPy import IP
 from ..setting import undefined, Undefined, OptionBag
 from ..i18n import _
 from .option import Option
+from .stroption import StrOption
 
 
-class DomainnameOption(Option):
+class DomainnameOption(StrOption):
     """represents the choice of a domain name
     netbios: for MS domain
     hostname: to identify the device
diff --git a/tiramisu/option/emailoption.py b/tiramisu/option/emailoption.py
index 1d4886a..89432cb 100644
--- a/tiramisu/option/emailoption.py
+++ b/tiramisu/option/emailoption.py
@@ -21,7 +21,7 @@
 import re
 
 from ..i18n import _
-from .option import RegexpOption
+from .stroption import RegexpOption
 
 
 class EmailOption(RegexpOption):
diff --git a/tiramisu/option/filenameoption.py b/tiramisu/option/filenameoption.py
index 1142a34..ef4ea69 100644
--- a/tiramisu/option/filenameoption.py
+++ b/tiramisu/option/filenameoption.py
@@ -21,7 +21,7 @@
 import re
 
 from ..i18n import _
-from .option import RegexpOption
+from .stroption import RegexpOption
 
 
 class FilenameOption(RegexpOption):
diff --git a/tiramisu/option/ipoption.py b/tiramisu/option/ipoption.py
index 3eab8a8..e417c1f 100644
--- a/tiramisu/option/ipoption.py
+++ b/tiramisu/option/ipoption.py
@@ -24,9 +24,10 @@ from ..error import ConfigError
 from ..setting import undefined, Undefined, OptionBag
 from ..i18n import _
 from .option import Option
+from .stroption import StrOption
 
 
-class IPOption(Option):
+class IPOption(StrOption):
     "represents the choice of an ip"
     __slots__ = tuple()
     _display_name = _('IP')
diff --git a/tiramisu/option/netmaskoption.py b/tiramisu/option/netmaskoption.py
index 80a2a5d..0d33112 100644
--- a/tiramisu/option/netmaskoption.py
+++ b/tiramisu/option/netmaskoption.py
@@ -24,9 +24,10 @@ from ..error import ConfigError
 from ..setting import undefined, OptionBag, Undefined
 from ..i18n import _
 from .option import Option
+from .stroption import StrOption
 
 
-class NetmaskOption(Option):
+class NetmaskOption(StrOption):
     "represents the choice of a netmask"
     __slots__ = tuple()
     _display_name = _('netmask address')
diff --git a/tiramisu/option/passwordoption.py b/tiramisu/option/passwordoption.py
index bab8225..8366757 100644
--- a/tiramisu/option/passwordoption.py
+++ b/tiramisu/option/passwordoption.py
@@ -22,9 +22,10 @@
 from ..setting import undefined, Undefined, OptionBag
 from ..i18n import _
 from .option import Option
+from .stroption import StrOption
 
 
-class PasswordOption(Option):
+class PasswordOption(StrOption):
     "represents the choice of a password"
     __slots__ = tuple()
     _display_name = _('password')
diff --git a/tiramisu/option/portoption.py b/tiramisu/option/portoption.py
index 5a39861..4a6ea56 100644
--- a/tiramisu/option/portoption.py
+++ b/tiramisu/option/portoption.py
@@ -25,9 +25,10 @@ from typing import Union
 from ..setting import undefined, Undefined, OptionBag
 from ..i18n import _
 from .option import Option
+from .stroption import StrOption
 
 
-class PortOption(Option):
+class PortOption(StrOption):
     """represents the choice of a port
     The port numbers are divided into three ranges:
     the well-known ports,
@@ -101,8 +102,6 @@ class PortOption(Option):
                   value: Union[int,str],
                   option_bag: OptionBag,
                   current_opt: Option=Undefined) -> None:
-        if isinstance(value, int):
-            value = str(value)
         if not isinstance(value, str):
             raise ValueError(_('invalid string'))
         if self.impl_get_extra('_allow_range') and ":" in str(value):
diff --git a/tiramisu/option/stroption.py b/tiramisu/option/stroption.py
index a0f9022..e28b375 100644
--- a/tiramisu/option/stroption.py
+++ b/tiramisu/option/stroption.py
@@ -19,6 +19,7 @@
 # the whole pypy projet is under MIT licence
 # ____________________________________________________________
 import sys
+from typing import Any
 
 from ..setting import undefined, Undefined, OptionBag
 from ..i18n import _
@@ -42,3 +43,17 @@ class StrOption(Option):
 class UnicodeOption(StrOption):
     __slots__ = tuple()
     _display_name = _('unicode')
+
+
+class RegexpOption(StrOption):
+    __slots__ = tuple()
+
+    def _validate(self,
+                  value: Any,
+                  option_bag: OptionBag,
+                  current_opt: Option=Undefined) -> None:
+        if not isinstance(value, str):
+            raise ValueError(_('invalid string'))
+        match = self._regexp.search(value)
+        if not match:
+            raise ValueError()
diff --git a/tiramisu/option/usernameoption.py b/tiramisu/option/usernameoption.py
index 0732c73..1882051 100644
--- a/tiramisu/option/usernameoption.py
+++ b/tiramisu/option/usernameoption.py
@@ -21,7 +21,7 @@
 import re
 
 from ..i18n import _
-from .option import RegexpOption
+from .stroption import RegexpOption
 
 
 class UsernameOption(RegexpOption):