Copyright © 2005 INL
This documentation is distributed under the Free Documentation Licence. Before reading/copying/using this documentation, please make sure you have read and accepted the licence. See http://www.gnu.org/licenses/licenses.html#FDL
| Revision History | |
|---|---|
| Revision 0.1 | 2005/03/22 |
|
Initial release | |
| Revision 0.1.1 | 2005/08/10 |
|
Documented new "Modified" and "Comment" fields. Various fixes. First complete english translation. | |
| Revision 0.1.2 | 2005/12/31 |
|
Acl groups now supported and documented | |
| Revision 0.1.3 | 2006/02/10 |
|
Documented nat rules | |
Table of Contents
Nuface web interface allows you to to configure a nufw based firewall (EdenWall), or a simple Netfilter firewall. With nuface, way of work is to use followings objects
subjects: the initiator of a connection : can be an IPv4 object or a NuFW authenticated user, or a combination (and/or) of both.
ressources: the source of a connection
protocols: used to define technical parameters of a connection: ports, icmp types, protocols, etc.
acls: use one element of each class defined above. An acl can lead to generate several firewall rules.
floatings: theses are working elements, used to easily manipulate and move objects that are handled by the web interface. The floatting elements are never saved to file, they are to be used within one session only.
Table of Contents
The firewall configuration interface is built of several sections which are described here.
The Index page lets you manage configuration files built with Nuface, and is an interface for several system tasks :
Load an existing configuration file
Save configuration to a new file, or by overwritting one
Delete a configuration file
Clear session : this forgets all current modifications. All current items of the interface are deleted
Filter rules: generate a ruleset file. This is to be done before loading the wanted ruleset
Reload firewall rules : puts rules generated by the former option into production. Two options are available :
nufw : load authenticating rules
standard : load backup (non-authenticating) rules
This is the main page of the interface, as it uses items built from other pages :
protocols : protocols definition page
subjects : definition page for the entities that are initiators of connections
ressources : definition page for the entitites that are protected by the firewall (destinations of connections)
Of course, one single object can be referenced both in Subjects and in Ressources. This page only works if a valid ACLs file was loaded through the index page.
On this page, you can :
Change order of acls. The higher an acl is, the higher its priority on others is. In other words, if two acls are mention different decisions for a given connection, the first in list will be applied.
Edit acls. You can change :
The acl name (this is just a label name)
The protocol(s) (group) used by this acl
The subject(s) (group) used by this acl
The ressource(s) (group) used by this acl
The acl's decision. Available decisions are :
Accept : accept connections matching given criterias
Drop : drop any packet matching given criterias, as if we never received it.
Reject : same as Drop, but let the sender know we refused their attempt
Ulog : advanced logging (ie, to database)
Log : standard logging (to syslog)
When dealing with an authenticating rule, only one of the two first decisions can be chosen. (The log is actually also provided through other means). Choosing Ulog or Log is not an actual decision. It gets the packet to be logged, but a decision remains to be taken by another acl.
The protocols definition page lists all protocols in use by the firewall. As for all items used in Nuface, you can gather items together into containers.
For instance, you could gather protocols HTTP and HTTPS into one
Websurf protocol entity, and use this
entity to genarate acls which will apply to either HTTP or HTTPS
traffic.
This page contains containers, which are, by definition, objects with nothing else than a label. Each container also gathers one or several elementary items, which can define data by themselves, or link to other containers. This way, you can combine items as you please without redefining already existing items.
Protocols elementary items can be assigned the following types of data:
name : name of the element (this is just a label)
proto : the protocol. Possible values of this field are:
tcp
udp
icmp
dport : destination port. (only valid if protocol is either
tcp or
udp)
sport : source port (only valid if protocol is either
tcp or
udp)
icmptype (only valid if protocol is
icmp)
ID : a nuface-assigned identifier, which you can not modify
"Link" typed elements can also be created on this page
The subjects definition page lists all subjects in use by the firewall. A so-called subject is an item that is at source of network traffic : an initiator of connexions. As for all items used in Nuface, you can gather items together into containers. There is one difference on this page, as compared to others : the subjects page is the only one that lets you choose the type of gathering you want to apply to objects. One of these two logical types of gathering must be chosen :
and : all elements of the group must match
or : if one element of the group matches, match is granted
For instance, lets gather these objects :
authenticated administrators and
admin_net into a container that we name
Admins. We will use this container on the
acls page to generate rules that deal with network traffic from
authenticated administrators and/or (depending on what we set here) the
admins network.
As for protocols, this page contains containers, which are, by definition, objects with nothing else than a label. Each container also gathers one or several elementary items, which can define data by themselves, or link to other containers. This way, you can combine items as you please without redefining already existing items.
Elementary items defined on the Subjects page are attributed the
following fields, if their type is ipv4:
name : element name (this is just a label)
net : network address (can be one single IP address or a network address)
mark : this is the same mark as the one set in the VPN configuration file. This mark, which is used by the Kernel, guarantees no spoofing is possible in the VPN tunnel.
ID : a nuface-assigned identifier, which you can not modify
Elementary items defined on the Subjects page are attributed the
following fields, if their type is nufw:
nufw:
name : element name (this is just a label)
group : the group number, matching a group of users on your Users Directory (LDAP, Active Directory, NT domain, etc.).
ID : a nuface-assigned identifier, which you can not modify
"Link" typed elements can also be created on this page
The ressources definition page lists all ressources in use by the firewall. A so-called Ressource is always a network object, that receives a connexion launched from a Subject. As for all items used in Nuface, you can gather items together into containers.
For instance, you could gather protocols HTTP and HTTPS into one
Websurf protocol entity, and use this
entity to genarate acls which will apply to either HTTP or HTTPS
traffic.
As for protocols and subjects, this page contains containers, which are, by definition, objects with nothing else than a label. Each container also gathers one or several elementary items, which can define data by themselves, or link to other containers. This way, you can combine items as you please without redefining already existing items.
Elementary items defined on the Ressources page are attributed the following fields :
name : element name (this is just a label)
net : network address (can be one single IP address or a network address)
mark : this is the same mark as the one set in the VPN configuration file. This mark, which is used by the Kernel, guarantees no spoofing is possible in the VPN tunnel.
ID : a nuface-assigned identifier, which you can not modify
"Link" typed elements can also be created on this page
This page deals with Network Addresses Tranlation rules. Nuface allows administrators to create and manage three kinds of nat rules:
SNAT: source nat, theses rules are used to rewrite source address of connections.
DNAT: used to rewrite destination address and destination port of connections.
PNAT: translate only connection port
Rules defined on the nat page are attributed the following fields:
name: rule name (this is just a label)
Source address: connection source address
Dest. Address: connection destination address
Protocol: protocol of the connection. Possible values of this field are:
tcp
udp
icmp
Sport: connection source port (only valid if protocol is either
tcp or
udp)
Dport: connection destination port (only valid if protocol is either
tcp or
udp)
icmp)Destination and source addresses represent either networks addresses or only one IP address.
With DNAT rules, the Rewrite destination to field is the new destination address and new destination port of the connection.
Rewrite source to field of SNAT rules is the new connection source address.
With PNAT rules, the Rewrite port to field is the new destination port of the connection.
From version 0.9.3 on, all items of the interface, containers and elements, are attributed two more fields : Comment and modified.
This field is for the administrator to set informations to ease life of items of the interface, and their tracking. This field is never used by Nuface's engine, and is only useful to the human users of the interface.
Table of Contents
Subjects, ressources and protocols are organized with containers. Containers are nothing else than a cockle, which contains one or several elements. Containers are used to provide a structure to acls, and never define data by themselves. There are three types of containers :
subjects : gathers elements that describe what is at source of connexions.
ressources : elements of such containers are used to define network objects that are destinations of some connexions managed by the firewall.
protocols : this type of container defines protocols.
Always try to create containers that match a consistent entity. For instance, use a Subject container to gather two network addresses, so the container could be called "All addresses of your intranet". Do the same with protocols, to create protocols "groups" which would match a number of protocols to open so that one application works fine.
Elements are the most basic bricks of an acl set. Elements contain actual data, as opposed to containers which define a structure of elements. There exists several types of elements :
ipv4 : define network objects ; these can be used in Subjects or Ressources containers.
proto : can be used only in Protocols containers.
nufw : can be used only in Subjects containers. Elements of this type define user groups authenticated through NuFW.
link : can be used in any container. Link elements are used to gather several containers into one, in order to create a more complex or complete group.
Lets imagine you want to create an acl to allow SMTP access from the Internet to your DMZ mail server. We shall define the following elements :
A subject named "Internet", which must define the 0.0.0.0/0 network.
A protocol named "SMTP", defining TCP as protocol, destination port 25, source port higher than 1024
A ressource, which will here be defined as the IP address of our server.
Each element is stored in a container of its type ; it is the containers that are dealt by the acl, which also has an "accept" decision.
As a more complex example, you might want to allow a network to surf the internet, either on HTTP or HTTPS. Such a case makes links useful. The HTTP and HTTPS protocols are defined by default ; we create a new protocol container, named "websurf", and containing two links elements, pointing to the HTTP and to the HTTPS containers. We will use our "Websurf" protocol to build the Acl we want, so it will match all HTTP and HTTPS connexions.
An ACL is the glue that links containers of subjects, ressources, and possibly protocols. Each Acl also contains a decision. Since Acls are built with containers of all types, the acl creation phase is usually the last phase, since other containers must exist to feed the acl. Don't forget order of Acls matters.
A group is an entity that lets you activate or disable a set of Acls. By default, all created Acls belong to the default group, which is enabled by default. To create a group, go to the Acls page, and use the form at the top of the page. To switch an Acl's group, edit that Acl and pick the desired group from the list. Acls that belong to disabled groups are displayed in grey in the Acls page. Those will not be taken into account next time you generate filtering rules.
All Acls are displayed with a geometric symbol which is a marker of the group they belong to.
Note : One given Acl can only belong to one group at a given moment
Table of Contents
This type is to define network elements : simple addresses or
network addresses. Elements of this type are to be used in
subjects or in
ressources containers, and lets you
target an acl to an IP address or to a network address.
Ce type sert à définir des éléments de réseaux : adresses simples ou adresses de réseaux. Utilisé aussi bien dans les conteneurs sujets que ressources, il permet de cibler les acls sur une machine ou un réseau.
This type of element can only be used in
subjects containers, and is used to
define a group of NuFW users. Acls using this container will then match
only users belonging to the chosen group.
This type of element can only be used in
protocols containers. It defines a
protocol, and is set the following fields :
proto which is tcp, udpor icmp.
Depending on the chosen proto, the
dport (destination port),
sport (source port) and
icmptype (icmp type) fields can also be
set. Concerning port numbering, ranges can of course be specified, such
as 1024:65535, which means "all ports
from 1024 to 65535".
It is easy to copy an element from a container to another, or from
a page to another (for instance, copy an ipv4 element from the
ressources page to the subjects page). Select the element to copy, and
use the Copy to Floating button.
Then, move to the target container, and use the
Add button on top right to complete the
copy.
Floating elements are just temporary elements, which disapear when you close a Nuface session. They are to be used for copying and creating elementary items used by Nuface.
Choose the
floatings page, select the element type
you want, and use the
New element button. Note that the type
of a given element can never be changed. Each element is attributed its
type forever.
A good habbit is to create in the floatings page one empty element of each type, and use them when needed, by copying them into the protocols, subjects or ressources pages.