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Mon Jul 22 08:44:30 2013 UTC (10 years, 11 months ago) by misho
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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>PPTP 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: : PPTP device type commands  12: Previous: <A HREF="mpd46.html">UDP device type commands</A>  13: Next: <A HREF="mpd48.html">L2TP device type commands</A> 14: 15: 16: <HR NOSHADE> 17: <H2><A NAME="47"></A>5.5. PPTP device type commands<A NAME="pptp"></A></H2> 18: This chapter describes commands that are specific to PPTP type links. 19: These commands apply to the currently active link, and are only 20: valid if the currently active link has type pptp. 21: The PPTP protocol can be most easily understood as just another 22: link layer type, where the link layer medium just happens to be 23: an IP connection. So, for example, instead of configuring a 24: telephone number to dial as you would with a modem, you configure 25: an IP address to connect to. Everything else that's above the 26: link layer functions exactly the same. Hence PPTP allows you 27: to ``tunnel'' PPP frames over IP. 28: Note that PPTP connections are initiated by a TCP connection from 29: one machine to another, and that servers usually listen to TCP 30: port 1723 (and this is the default for <code>port</code> 31: in the commands below). PPTP also uses the GRE protocol, which 32: has IP protocol number 47. Your firewall may need to be adjusted 33: to allows this type of IP packet. 34: Complete PPTP network topology looks like: 35: <pre> 36: client <- some link type -> PAC <- PPTP tunnel -> PNS 37: </pre> 38:  39: PAC is physical level repeater, which receives PPP connection of some 40: type and forwards it to PNS using PPTP protocol. PNS is a PPP endpoint, 41: which receives PPP frames via PPTP tunnel and processes them. 42: In simple case, when physical conversion is not required, topology 43: can be simplified to: 44: <pre> 45: client (PAC emulator) <- PPTP tunnel -> PNS 46: </pre> 47:  48: Mpd is able to operate in both PAC and PNS modes. As PAC mpd supports 49: both simple case PAC emulator and complete PAC topologies. Complete 50: PAC can be configured by joining two physical devices using mpd's 51: repeater functionality. 52:  53: <dl> 54: 55: <dt><code>set pptp self ipaddr [ port ]</code><dd>Sets the local IP address and port for the PPTP connection. 56: 57: <dt><code>set pptp peer ipaddr [ port ]</code><dd>Sets the peer IP address and port for the PPTP connection. 58: This command applies to both incoming and outgoing connections. 59: For outgoing connections, this command is required in order to 60: specify where to connect to. For incoming connections, this command 61: is optional; if not given, mpd accepts incoming connections from any 62: host. Otherwise, only connections from the stated IP address 63: (and, optionally, port) are allowed. 64: 65: <dt><code>set pptp callingnum number</code><dd> 66: <dt><code>set pptp callednum number</code><dd>Sets the calling and called telephone number to use when initiating a PPTP 67: connection. For most VPN applications this is ignored, but in certain 68: cases an actual phone number is required. 69: The default is the empty string. 70: 71: <dt><code>set pptp enable option ... </code><dd> 72: <dt><code>set pptp disable option ... </code><dd> 73: Enable and disable PPTP device type options for the link. 74: 75: </dl> 76:  77: 78: The following options are supported: 79:  80: <dl> 81: 82: <dt><code>outcall</code><dd>In PPTP, each individual PPP connection between two IP hosts (there 83: may be several, and these are not to be confused with the 84: single TCP connection between any two IP hosts), is 85: initiated as either an incoming or an outgoing call. 86: This allows to make an outgoing phone call (by PNS) via a remote access 87: server (PAC), as well as in more common case forward an incoming 88: phone call from an access server (PAC) to a remote PPTP server (PNS). 89: When this option is enabled, mpd will initiate outgoing calls (PNS); 90: otherwise mpd will initiate incoming calls (PAC). Although it seems that 91: incoming would be more correct, the default is outgoing, as this 92: is consistent with the behavior of the Microsoft PPTP dial-up adapter 93: client. 94: Mpd will accept either type of call on an incoming PPTP connection. 95: 96: <dt><code>delayed-ack</code><dd>Enable delayed ACK's. This can improve throughput on reliable links. 97: The default is enable. 98: 99: <dt><code>always-ack</code><dd>Always include ACK even if already sent. This can improve throughput 100: on unreliable links. 101: The default is disable. 102: 103: <dt><code>windowing</code><dd>Enables the windowing mechanism specified by the protocol. Disabling 104: this will cause Mpd to violate the protocol, possibly confusing some 105: PPTP peers, but usually results in better performance. The windowing 106: mechanism is a design error in the PPTP protocol; L2TP, the successor 107: to PPTP, removes it. 108: The default is disable. 109: 110: <dt><code>resolve-once</code><dd>Enables resolving peer address only once, on startup, or on manual 111: typing in CLI. 112: The default is enable. 113: 114: </dl> 115:  116: Note that if you are connecting to an NT server, your authentication 117: name must include the NT domain name. For example: 118:  119: <blockquote><code> 120: <pre> 121: set auth authname "DOMAIN\\username" 122: </pre> 123: </code></blockquote> 124:  125: For updating Windows 95 and 98 clients so they work properly, see 126: <A href="http://support.microsoft.com/default.aspx?scid=KB;EN-US;Q191540">http://support.microsoft.com/default.aspx?scid=KB;EN-US;Q191540</A> 127: 128: 129: 130: <HR NOSHADE> 131: <A HREF="mpd.html">Mpd 5.7 User Manual</A> 132: : <A HREF="mpd42.html">Device Types</A> 133: : PPTP device type commands  134: Previous: <A HREF="mpd46.html">UDP device type commands</A>  135: Next: <A HREF="mpd48.html">L2TP device type commands</A> 136: 137: 138: 139: </BODY> 140: </HTML>