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Mon Jul 22 08:44:30 2013 UTC (10 years, 11 months ago) by misho
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CVS tags: v5_7p0, v5_7, HEAD

5.7

1: <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 3.2 Final//EN"> 2: <HTML> 3: <HEAD> 4: <META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1"> 5: <TITLE>L2TP device type commands</TITLE> 6: </HEAD> 7: <BODY text="#000000" bgcolor="#ffffff"> 8: 9: <A HREF="mpd.html">Mpd 5.7 User Manual</A> 10: : <A HREF="mpd42.html">Device Types</A> 11: : L2TP device type commands  12: Previous: <A HREF="mpd47.html">PPTP device type commands</A>  13: Next: <A HREF="mpd49.html">PPPoE device type commands</A> 14: 15: 16: <HR NOSHADE> 17: <H2><A NAME="48"></A>5.6. L2TP device type commands<A NAME="l2tp"></A></H2> 18: This chapter describes commands that are specific to L2TP type links. 19: These commands apply to the currently active link, and are only 20: valid if the currently active link has type l2tp. 21: The L2TP protocol utilizes UDP datagrams on port 1701 (and this is 22: the default for <code>port</code> in the commands below) 23: to create and maintain virtual tunnel between IP peers. 24: One or more independent PPP connections (sessions) can be 25: carried inside this tunnel. 26: Complete L2TP network topology looks like: 27: <pre> 28: client <- some link type -> LAC <- L2TP tunnel -> LNS 29: </pre> 30:  31: LAC is physical level repeater, which receives PPP connection of some 32: type and forwards it to LNS using L2TP protocol. LNS is a PPP endpoint, 33: which receives PPP frames via L2TP tunnel and processes them. 34: In simple case, when physical conversion is not required, topology 35: can be simplified to: 36: <pre> 37: client (LAC emulator) <- L2TP tunnel -> LNS 38: </pre> 39:  40: Mpd is able to operate in both LAC and LNS modes. As LAC mpd supports 41: both simple case LAC emulator and complete LAC topologies. Complete 42: LAC can be configured by joining two physical devices using mpd's 43: repeater functionality. 44: Windows L2TP client uses IPSec encryption for the additional tunnel 45: security. So, to let it connect you must configure IPSec on your 46: MPD router or disable IPSec on Windows by setting registry 47: DWORD value ProhibitIpSec at the key 48: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\RasMan\Parameters\ 49: into "1". 50:  51: <dl> 52: 53: <dt><code>set l2tp self ipaddr [ port ]</code><dd>Sets the local IP address and port for the L2TP connection. 54: There is known implementation bug if this option is not set 55: while accepting incoming connections on the router with multiple 56: IPs and clients are connecting not to the nearest address of 57: this router. 58: 59: <dt><code>set l2tp peer ipaddr [ port ]</code><dd>Sets the peer IP address and port for the L2TP connection. 60: This command applies to both incoming and outgoing connections. 61: For outgoing connections, this command is required in order to 62: specify where to connect to. For incoming connections, this command 63: is optional; if not given, mpd accepts incoming connections from any 64: host. Otherwise, only connections from the stated IP address 65: (and, optionally, port) are allowed. 66: 67: <dt><code>set l2tp hostname name</code><dd>Sets the L2TP tunnel local hostname. For server side, only one 68: unique hostname supported for every pair of listening IP (set l2tp self ...) 69: and peer ip (set l2tp peer ...). 70: If several hostnames defined, only the first matching will be used for all 71: incoming connections. 72: 73: <dt><code>set l2tp secret secret</code><dd>Sets the L2TP tunnel secret. Used to authenticate tunnel connection 74: and encrypt important control packets avpairs. For server side, only 75: one unique secret supported for every pair of listening IP (set l2tp self ...) 76: and peer ip (set l2tp peer ...). 77: If several secrets defined, only the first matching will be used for all 78: incoming connections. 79: NOTE: This options is not related with usual PPP authentication. 80: Windows client does not support tunnel authentication. 81: 82: <dt><code>set l2tp callingnum number</code><dd> 83: <dt><code>set l2tp callednum number</code><dd>Sets the calling and called telephone number to use when initiating a L2TP 84: connection. For most VPN applications this is ignored, but in certain 85: cases an actual phone number is required. 86: The default is the empty string. 87: 88: <dt><code>set l2tp enable option ... </code><dd> 89: <dt><code>set l2tp disable option ... </code><dd> 90: Enable and disable L2TP device type options for the link. 91: 92: </dl> 93:  94: 95: The following options are supported: 96:  97: <dl> 98: 99: <dt><code>outcall</code><dd>Inside L2TP tunnel, each individual PPP connection (there may be several), 100: is initiated as either an incoming or an outgoing call. 101: This allows to make an outgoing phone call (by LNS) via a remote access 102: server (LAC), as well as in more common case forward an incoming 103: phone call from an access server (LAC) to a remote L2TP server (LNS). 104: When this option is enabled, mpd will initiate outgoing calls (LNS); 105: otherwise mpd will initiate incoming calls (LAC). 106: The default is disable. 107: 108: <dt><code>hidden</code><dd>When L2TP tunnel secret is configured it is possible hide (encrypt) some 109: control data for additional protection. 110: The default is disable. 111: 112: <dt><code>length</code><dd>By default L2TP uses header Length field for control packets, but not for 113: data packets. This option enables Length field for data packets. 114: This feature enabled may be useful on links where packets padding may 115: happend. Disabling it reduces overhead by 2 bytes per packet. 116: The default is disable. 117: 118: <dt><code>dataseq</code><dd>By default L2TP requires header sequence fields for control packets, but 119: not require them for data packets. This option enables sequence fields for 120: data packets. 121: This feature enabled may be useful on links where packets reordering may 122: happend but it is intolerable. Disabling it reduces overhead by 4 bytes per packet. 123: The default is enable. 124: 125: <dt><code>resolve-once</code><dd>Enables resolving peer address only once, on startup, or on manual 126: typing in CLI. 127: The default is enable. 128: </dl> 129:  130: 131: 132: 133: <HR NOSHADE> 134: <A HREF="mpd.html">Mpd 5.7 User Manual</A> 135: : <A HREF="mpd42.html">Device Types</A> 136: : L2TP device type commands  137: Previous: <A HREF="mpd47.html">PPTP device type commands</A>  138: Next: <A HREF="mpd49.html">PPPoE device type commands</A> 139: 140: 141: 142: </BODY> 143: </HTML>