NuFace : Administrator manual

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Revision History
Revision 0.12005/03/22

Initial release

Revision 0.1.12005/08/10

Documented new "Modified" and "Comment" fields. Various fixes. First complete english translation.

Revision 0.1.22005/12/31

Acl groups now supported and documented

Revision 0.1.32006/02/10

Documented nat rules

Revision 0.22006/12/27

Added informations about nuface 1.2

Revision 0.2.12007/02/15

L7-filter filtering documentation


Table of Contents

1. General Introduction
2. Interface's elements
Index
Acls
Protocols
Subjects
Resources
Applications
Periods
l7rules
Nat
Changes management and tracking
The Comment field
The Modified field
3. Items used by Nuface
Containers
Definition
How to use containers
Elements
Definition
Examples
Acls
Definition
Groups
Sorting Acls
4. Details about elements
Element types
The ipv4 type
The nufw type
The proto type
The period type
The app type
The link type
How to create an element
Copy an existing element
Creating an element from scratch

Chapter 1. General Introduction

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. If you don't use a NuFW firewall, you can set the

    $show_subjects

    variable to false, and the resources will be considered as subjects.

  • resources: the destination 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.

  • applications : of use only on a NuFW firewall. This lets you filter based on application/OS advertised by the NuFW client.

  • periods : lets you define time ranges in your ACLs. Only can be used with NuFW subjects.

  • l7rules : deals with layer 7 inspection. L7rules can be setup to match protocols, for instance to check that traffic on TCP port 80 is actually HTTP. These features lay on l7-filter, which is available at http://l7-filter.sourceforge.net. If your firewall supports l7-filter, set

    $l7_firewall=true;

    in nuface config file.

  • 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.

Chapter 2. Interface's elements

The firewall configuration interface is built of several sections which are described here.

Index

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

Acls

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

  • resources : definition page for the entitites that are protected by the firewall (destinations of connections)

  • applications : for authenticating firewalls only, and for an ACL with a NuFW subject, lets you filter per application or per OS.

  • periods : for authenticating firewalls only, and for an ACL with a NuFW subject, lets you filter according to time/date/duration criterias.

Of course, one single object can be referenced both in Subjects and in Resources. 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 (group) used by this acl

    • The subject (group) used by this acl

    • The resource (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.

Beware of ordering problems on your ACLs. Generally, try to always keep first the particular ACLs, and keep last the more general ACLs. For instance, if you want to allow HTTP traffic from IP address 10.2.3.4 (acl 1), and also allow HTTP for authenticated users on the 10.0.0.0/8 network (acl 2), it is important that ACL 1 be ordered before ACL 2, else ACL 2 will never be applied.

Protocols

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)

  • l7rule : a layer7 rule to match the protocol, if needed. This item is only available if you have $l7_firewall=true; in nuface config file.

  • ID : a nuface-assigned identifier, which you can not modify

"Link" typed elements can also be created on this page

Subjects

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

If you do not use an authenticating NuFW firewall, you can choose to merge your subjects and resources. This means you only set up resources, no subjects, and ACLs will accept any resource object as subject. You can set this in the include/config.php file by setting the

$show_subjects

parameter to false.

Resources

The resources definition page lists all resources in use by the firewall. A so-called Resource 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 Resources 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

Applications

Applications can be used only in ACLs that deal with NuFW subjects. Applications objects let you setup ACLs based on :

  • applicationpath : An application full name, as announced by the NuFW client. For instance : "C:\Program Files\Firefox\firefox.exe"

  • OSName : the name of the OS advertized by the Nufw client.

  • OSVersion : the version of the OS advertized by the client.

This menu is not displayed if you set

$nufw_firewall = false

in nuface config file.

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.

Periods

Periods can be used only in ACLs that deal with NuFW subjects. Periods objects let you setup ACLs based on periodtypes, which can be :

  • dates : by specifying a start and an end in epoch time (number of seconds since 1970, Jan 1st).

  • days : by specifying a start and an end day of week day (numbered from 1 to 7, starting on monday).

  • hours : by specifying a start and end hour (numbered from 0 to 24)

  • duration : by specifying a number of seconds that will be the max duration of the associated connexion.

This menu is not displayed if you set

$nufw_firewall = false

in nuface config file.

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.

l7rules

l7rules can be defined and used if you have :

L7rules are particular objects, which contain their own default actions :

  • accept : default action of the l7rule is to let the packet through

  • ulogaccept : same as accept, but also log the event into ULOG

  • ulogdrop : drop the packet, and log it to ULOG

  • logaccept : same as accept, but also log the event to SYSLOG

  • logdrop : drop the packet, and log it to SYSLOG

L7Rule objects also have a logprefix attribute, which should contain the text that you want to be logged when the l7rule will trigger any logging.

L7rule objects contain l7proto elements, which should ususally specify actual protocol matching, and decisions. Ususally, the decision of a l7proto object should be opposite to the default decision of the l7rule container.

L7proto elements provide the following attributes :

  • name : a textual name of your choice

  • ID : a numeric identifier set by nuface, which you cannot change

  • l7proto : an actual protocol known by l7-filter. The list of available protocols is available at http://l7-filter.sourceforge.net/protocols. Note that the default list available from nuface is only a subset of the online list : this subset was chosen by the Nuface development team. You can extend it by modifying the include/l7-protos text file, if you know what you are doing.

  • action : what to do when the l7proto protocol is detected. Available actions are :

    • accept

    • ulogaccept

    • ulogdrop

    • logaccept

    • logdrop

  • prefix : if the action mentions logging, what prefix nuface should add to the log. This is, of course, a field of plain text.

  • modified : date of last modification of this field ; this is automatically set by nuface

  • comment : a field you can fill with any information you fill. Nuface remembers it but doesn't use it for any technical task.

Nat

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 type (only activated if protocol is 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.

Changes management and tracking

From version 0.9.3 on, all items of the interface, containers and elements, are attributed two more fields : Comment and modified.

The Comment field

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.

The Modified field

This field is set by Nuface, for each item of the interface. Nuface updates it whenever the item is modified by an administrator. The administrator can never change this field's value.

Chapter 3. Items used by Nuface

Containers

Definition

Subjects, resources 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.

  • resources : 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.

How to use containers

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

Definition

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 Resources 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.

Examples

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 resource, 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.

Acls

Definition

An ACL is the glue that links containers of subjects, resources, 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.

Groups

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

Sorting Acls

Things have evolved from nuface 1.0 to nuface 1.2 : this is one of the major evolutions of 1.2. In Nuface 1.2, the global ACL menu does not allow to change order of ACLs anymore. Indeed, ACLs ordering is still possible and flexible, but only in a network context. For instance, if you set 2 ACLs, ACL A from network N1 to network N2, and ACL B from network N3 to network N4 (with N1,N2,N3,N4 having no intersection), ordering of ACLs A and B is a non sense. To order ACLs, switch to the concerned context from the ACL page and use drag and drop as usual. This ordering scheme is much more powerful than 1.0 was, and is also more intuitive. It is also easier to use when setting up multiple ACLs.

Chapter 4. Details about elements

Element types

The ipv4 type

This type is to define network elements : simple addresses or network addresses. Elements of this type are to be used in subjects or in resources containers, and let 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 resources, il permet de cibler les acls sur une machine ou un réseau.

The nufw type

This type of element contain a net attribute, which must contain a network object. A network object is either an IP address (192.168.33.1), or a network address (such as 10.0.0.0/255.0.0.0 or in CIDR format 10.0.0.0/8). The Internet is always defined as 0.0.0.0/0 and is auto-generated by Nuface if it does not exist when opening the ACLs file. After you create or modify a network object, Nuface displays the Network name the new element belongs to, according to your network topology.

The proto type

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".

The period type

This type of element can only be used in periods containers. It defines a period, and is set the following fields : periodtype which is dates, days, hours or duration. Depending on the chosen periodtype, the start, end and duration fields can also be set.

The app type

This type of element can only be used in applications containers. It defines an application, and is set the following fields : ApplicationPath, the complete name of the application at source of the IP connection, as advertized by the NuFW client, OSName, the name of the OS at source of the IP connection, as advertized by the NuFW client. OSVersion, the version of the OS at source of the IP connection, as advertized by the NuFW client. set.

The link type

This type of element can be used in any container, and lets you create a link to another container of the same type. Using such a link is equivalent as using the pointed container, which allows for easy aggregating of data into one container.

How to create an element

Copy an existing element

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 resources 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.

Creating an element from scratch

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 resources pages.