X-Git-Url: http://git.sameswireless.fr/l2tpns.git/blobdiff_plain/1eb066f4db51b1bae4ed9ade5ac51311fb78468f..8261839e1625710ec2c3db3bb569f5dfb5881fa3:/Docs/manual.html?ds=sidebyside diff --git a/Docs/manual.html b/Docs/manual.html index ba62c5d..ff7f0b3 100644 --- a/Docs/manual.html +++ b/Docs/manual.html @@ -52,9 +52,11 @@ H3 {
  • Interception
  • Authentication
  • Plugins
    • -
  • Walled Garden
    • +
  • Walled Garden
    • +
  • Filtering
  • Clustering
  • Routing
    • +
  • Avoiding Fragmentation
  • Performance
    • @@ -66,7 +68,7 @@ L2TP (Layer 2 Tunneling Protocol) is designed to allow any layer 2 protocol (e.g. Ethernet, PPP) to be tunneled over an IP connection. l2tpns implements PPP over L2TP only.

    -There are a couple of other L2TP imlementations, of which l2tpd is probably the most popular. l2tpd also will handle being either end of a tunnel, and is a lot more configurable than l2tpns. However, due to the way it works, @@ -146,6 +148,7 @@ set ipaddress 192.168.1.1 set boolean true +

    +

    BGP routing configuration is entered by the command: +The routing configuration section is entered by the command +

    router bgp as
    +where as specifies the local AS number. + +

    Subsequent lines prefixed with +

    neighbour peer
    +define the attributes of BGP neighhbours. Valid commands are: +
    +
    neighbour peer remote-as as +
    neighbout peer timers keepalive hold +
    + +Where peer specifies the BGP neighbour as either a hostname or +IP address, as is the remote AS number and keepalive, +hold are the timer values in seconds. + +

    Named access-lists are configured using one of the commands: +

    +
    ip access-list standard name +
    ip access-list extended name +
    + +

    Subsequent lines prefixed with permit or deny +define the body of the access-list. Standard access-list syntax: +

    +
    {permit|deny} + {host|source source-wildcard|any} + [{host|destination destination-wildcard|any}] +
    + +Extended access-lists: + +
    +

    {permit|deny} ip + {host|source source-wildcard|any} + {host|destination destination-wildcard|any} [fragments] +

    {permit|deny} udp + {host|source source-wildcard|any} + [{eq|neq|gt|lt} port|range from to] + {host|destination destination-wildcard|any} + [{eq|neq|gt|lt} port|range from to] + [fragments] +

    {permit|deny} tcp + {host|source source-wildcard|any} + [{eq|neq|gt|lt} port|range from to] + {host|destination destination-wildcard|any} + [{eq|neq|gt|lt} port|range from to] + [{established|{match-any|match-all} + {+|-}{fin|syn|rst|psh|ack|urg} + ...|fragments] +

    +

    users

    Usernames and passwords for the command-line interface are stored in @@ -411,8 +449,7 @@ A running l2tpns process can be controlled in a number of ways. The primary method of control is by the Command-Line Interface (CLI).

    You can also remotely send commands to modules via the nsctl client -provided. This currently only works with the walled garden module, but -modification is trivial to support other modules.

    +provided.

    Also, there are a number of signals that l2tpns understands and takes action when it receives them. @@ -517,19 +554,19 @@ IP Address Used Session User

  • show radius
    -Show a summary of the in-use radius sessions. This list should not be very -long, as radius sessions should be cleaned up as soon as they are used. The +Show a summary of the in-use RADIUS sessions. This list should not be very +long, as RADIUS sessions should be cleaned up as soon as they are used. The columns listed are: - + - -
    RadiusThe ID of the radius request. This is - sent in the packet to the radius server for identification.
    RadiusThe ID of the RADIUS request. This is + sent in the packet to the RADIUS server for identification.
    StateThe state of the request - WAIT, CHAP, AUTH, IPCP, START, STOP, NULL.
    SessionThe session ID that this radius +
    SessionThe session ID that this RADIUS request is associated with
    RetryIf a response does not appear to the request, it will retry at this time. This is a unix timestamp.
    TryRetry count. The radius request is +
    TryRetry count. The RADIUS request is discarded after 3 retries.

    @@ -570,7 +607,7 @@ current session for that username will be forwarded to the given host/port. Specify no snoop username to disable interception for the session.

    -If you want interception to be permanent, you will have to modify the radius +If you want interception to be permanent, you will have to modify the RADIUS response for the user. See Interception.

    • @@ -581,7 +618,7 @@ session. Specify no throttle username to disable throttling for the current session.

    If you want throttling to be permanent, you will have to modify the -radius response for the user. See Throttling. +RADIUS response for the user. See Throttling.

    @@ -642,16 +679,13 @@ this way, although some may require a restart to take effect.

    nsctl

    -nsctl was implemented (badly) to allow messages to be passed to modules.

    +nsctl allows messages to be passed to plugins.

    -You must pass at least 2 parameters: host and command. The -host is the address of the l2tpns server which you want to send the message -to.

    +Arguments are command and optional args. See +nsctl(8) for more details.

    -Command can currently be either garden or ungarden. With -both of these commands, you must give a session ID as the 3rd parameter. -This will activate or deactivate the walled garden for a session -temporarily. +Built-in command are load_plugin, unload_plugin and +help. Any other commands are passed to plugins for processing.

    Signals

    @@ -662,16 +696,14 @@ killall -HUP l2tpns The signals understood are: - +
    +
    SIGHUP
    Reload the config from disk and re-open log file.
    +
    SIGTERM, SIGINT
    Stop process. Tunnels and sessions are not +terminated. This signal should be used to stop l2tpns on a +cluster node where there are other machines to +continue handling traffic.
    +
    SIGQUIT
    Shut down: closes sessions and tunnels.
    +

    Throttling

    @@ -680,7 +712,7 @@ desire. You must first enable the global setting throttle_speed before this will be activated.

    If you wish a session to be throttled permanently, you should set the -Vendor-Specific radius value Cisco-Avpair="throttle=yes", which +Vendor-Specific RADIUS value Cisco-Avpair="throttle=yes", which will be handled by the autothrottle module.

    Otherwise, you can enable and disable throttling an active session using @@ -704,7 +736,7 @@ and no snoop username CLI commands. These will enable interception immediately.

    If you wish the user to be intercepted whenever they reconnect, you will -need to modify the radius response to include the Vendor-Specific value +need to modify the RADIUS response to include the Vendor-Specific value Cisco-Avpair="intercept=yes". For this feature to be enabled, you need to have the autosnoop module loaded.

    @@ -714,11 +746,11 @@ Whenever a session connects, it is not fully set up until authentication is completed. The remote end must send a PPP CHAP or PPP PAP authentication request to l2tpns.

    -This request is sent to the radius server, which will hopefully respond with +This request is sent to the RADIUS server, which will hopefully respond with Auth-Accept or Auth-Reject.

    If Auth-Accept is received, the session is set up and an IP address is -assigned. The radius server can include a Framed-IP-Address field in the +assigned. The RADIUS server can include a Framed-IP-Address field in the reply, and that address will be assigned to the client. It can also include specific DNS servers, and a Framed-Route if that is required.

    @@ -728,7 +760,7 @@ walled garden module is loaded, in which case the user still receives the PPP AUTHACK, but their session is flagged as being a garden'd user, and they should not receive any service.

    -The radius reply can also contain a Vendor-Specific attribute called +The RADIUS reply can also contain a Vendor-Specific attribute called Cisco-Avpair. This field is a freeform text field that most Cisco devices understand to contain configuration instructions for the session. In the case of l2tpns it is expected to be of the form @@ -778,7 +810,7 @@ supplied structure: - - -
    EventDescriptionParameters
    pre_authThis is called after a radius response has been + This is called after a RADIUS response has been received, but before it has been processed by the code. This will allow you to modify the response in some way. @@ -795,7 +827,7 @@ supplied structure:
    post_authThis is called after a radius response has been + This is called after a RADIUS response has been received, and the basic checks have been performed. This is what the garden module uses to force authentication to be accepted. @@ -875,7 +907,7 @@ supplied structure:
    radius_responseThis is called whenever a radius response includes a + This is called whenever a RADIUS response includes a Cisco-Avpair value. The value is split up into key=value pairs, and each is processed through all modules. @@ -921,7 +953,7 @@ Walled Garden is implemented so that you can provide perhaps limited service to sessions that incorrectly authenticate.

    Whenever a session provides incorrect authentication, and the -radius server responds with Auth-Reject, the walled garden module +RADIUS server responds with Auth-Reject, the walled garden module (if loaded) will force authentication to succeed, but set the flag garden in the session structure, and adds an iptables rule to the garden_users chain to force all packets for the session's IP @@ -946,6 +978,14 @@ command: iptables -t nat -L garden -nvx +

    Filtering

    + +Sessions may be filtered by specifying Filter-Id attributes in +the RADIUS reply. filter.in specifies that the named +access-list filter should be applied to traffic from the +customer, filter.out specifies a list for traffic to the +customer. +

    Clustering

    An l2tpns cluster consists of of one* or more servers configured with @@ -993,6 +1033,22 @@ ibgp" for IBGP. If this is not supported by your IOS revision, you can use "maximum-paths" (which works for EBGP) and set as_number to a private value such as 64512.

    +

    Avoiding Fragmentation

    + +Fragmentation of encapsulated return packets to the LAC may be avoided +for TCP sessions by adding a firewall rule to clamps the MSS on +outgoing SYN packets. + +The following is appropriate for interfaces with a typical MTU of +1500: + +
    +iptables -A FORWARD -i tun+ -o eth0 	\
+    -p tcp --tcp-flags SYN,RST SYN	\
+    -m tcpmss --mss 1413:1600		\
+    -j TCPMSS --set-mss 1412
+
    +

    Performance

    Performance is great.