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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>Interface layer</TITLE> 6: </HEAD> 7: <BODY text="#000000" bgcolor="#ffffff"> 8: 9: <A HREF="mpd.html">Mpd 5.7 User Manual</A> 10: : <A HREF="mpd17.html">Configuring Mpd</A> 11: : Interface layer  12: Previous: <A HREF="mpd27.html">IPv6CP layer</A>  13: Next: <A HREF="mpd29.html">Authentication, Authorization and Accounting (AAA)</A> 14: 15: 16: <HR NOSHADE> 17: <H2><A NAME="28"></A>4.9. Interface layer<A NAME="interface"></A></H2> 18: 19: This chapter describes commands that configure the interface layer. 20: All of these commands apply to the currently active bundle. 21: Note that while most of the time mpd is used for transmitting 22: IP traffic, it is designed to support other (currently unimplemented) 23: protocols such as AppleTalk, IPX, etc. This is why the Interface 24: layer (which is protocol independent) is distinct from the 25: <A HREF="mpd26.html#ipcp">ipcp</A> which is specific to IP. 26:  27: <dl> 28: 29: <dt><code>set iface name [ name ]</code><dd>This command changes interface name from default ngX to specified one. 30: If name argument is not specified, original ngX name is restored. 31: Note that inside Netgraph original ngX name is always used. 32: 33: <dt><code>set iface description [ description ]</code><dd>This command changes interface description. 34: Template may contain conversion specifications: 35:  36: <pre> 37: %% expands to single % sign; 38: %a for interface local address; 39: %A for peer local address; 40: %i for system interface index; 41: %I for interface name; 42: %l for name of bundle's first link 43: %M for peer MAC address of bundle's first link 44: %S for interface status (DoD/UP/DOWN) 45: %t for type of bundle's first link (pppoe, pptp, l2tp etc.) 46: %u for self auth name (or dash if self auth name not used) 47: %U for peer auth name (or dash if peer has not authenticated) 48: </pre> 49:  50: 51: <dt><code>set iface group [ group ]</code><dd>This command add interface to specific group. 52: 53: <dt><code>set iface addrs [!]local-ip [!]remote-ip</code><dd>This command is usually required when dial-on-demand is enabled. 54: Normally, mpd configures the interface with the IP addresses that 55: were negotiated when connecting the link. Since dial-on-demand 56: configures the interface before actually connecting, mpd has to be 57: told initial local and remote IP addresses to give the interface. 58: These addresses don't have to correspond to the ``real'' ones; in 59: fact, both addresses can be completely fictional. If and when 60: different addresses are negotiated later, mpd will automatically 61: renumber the interface and adjust the routes. 62: Also this command may be used to force specified addresses usage 63: instead of negotiated ones. It may be useful in some specific cases, 64: for example, to avoid routing loop with misconfigured PPTP server. 65: In such case '!' mark specifies IPs to be forced. 66: 67: <dt><code>set iface route address[/width]</code><dd>This command associates a route with the bundle. Whenever the 68: interface is configured up, all associated routes are added. 69: A route of <code>default</code> indicates the default route. 70: Otherwise, the route is a network address with optional netmask 71: width (e.g., <code>192.168.1.0/24</code>). If the netmask 72: width is omitted, a single host route is assumed (i.e., a width 73: of 32). 74: Routes are automatically removed when the interface is brought down. 75: 76: <dt><code>set iface mtu value</code><dd>This command sets an upper bound on the MTU that will be configured 77: on the interface when the bundle comes up. 78: This value is not used at all during link negotiation; there are 79: separate bundle and link commands for configuring that. 80: Even if a higher bundle MTU is negotiated, this limit will still apply. 81: This command is useful when you want to manually restrict the MTU 82: of the interface for other reasons, e.g., if you're also doing IPSec. 83: The default is 1500. 84: 85: <dt><code>set iface idle seconds</code><dd>Sets the idle timeout value for the bundle. If no incoming or 86: outgoing packets are transmitted for <code>seconds</code> 87: seconds, the connection is brought down. An idle timeout of 88: zero disables this feature. 89: When the idle timeout occurs, if the dial-on-demand option is 90: enabled, mpd goes back into dial-on-demand mode. Otherwise, the 91: interface is brought down and all associated routes removed. 92: The default is 0. 93: 94: <dt><code>set iface session seconds</code><dd>Sets the session timeout value for the bundle. An session timeout of 95: zero disables this feature. 96: The default is 0. 97: 98: <dt><code>set iface up-script script </code><dd> 99: <dt><code>set iface down-script script </code><dd> 100: Mpd can optionally run a user program every time one of network 101: protocols (IPCP/IPv6CP) at the interface is brought up or down. 102: The <code>up-script</code> is called like this: 103: <blockquote><code> 104: <code>script interface proto local-ip remote-ip authname [ dns1 server-ip ] [ dns2 server-ip ] 105: peer-address</code> 106: </code></blockquote> 107:  108: If up-script exit status is not 0, mpd will kill respective protocol. 109: The <code>down-script</code> is called like this: 110: <blockquote><code> 111: <code>script interface proto local-ip remote-ip authname peer-address</code> 112: </code></blockquote> 113:  114: 115: <dt><code>set iface enable option ...  116: set iface disable option ...</code><dd>Enable and disable the various interface layer options for the bundle. 117: 118: </dl> 119:  120: 121: The options available at the interface layer are: 122:  123: <dl> 124: 125: <dt><code>on-demand</code><dd>This option causes the interface to operate in dial-on-demand mode, 126: allowing you to have a ``virtual full time'' connection. 127: An OPEN event causes the interface to be configured, but the actual 128: connection of the link is delayed until qualifying outgoing traffic 129: is detected. Moreover, after an idle timeout, the interface is not 130: brought down; further traffic will bring the link back up again. 131: The default is disable. 132: 133: <dt><code>proxy-arp</code><dd>When this option is enabled, if after link negotiation the peer's 134: IP address is determined to lie on a local subnet, then mpd will 135: arrange for the local machine to install a proxy ARP entry for 136: the remote machine's IP address. 137: For example, suppose the local machine lies on a LAN with address 138: 192.168.1.10, and another machine will be connecting via mpd 139: and using the LAN address 192.168.1.20. Then these commands would 140: set up proxy ARP for the remote machine: 141: <blockquote><code> 142: <code>set iface enable proxy-arp 143: set ipcp ranges 192.168.1.10/32 192.168.1.20/32</code> 144: </code></blockquote> 145:  146: The default is disable. 147: 148: <dt><code>tcpmssfix</code><dd>This option causes mpd to adjust incoming and outgoing TCP SYN 149: segments so that the requested maximum segment size is not greater 150: than the amount allowed by the interface MTU. 151: This is necessary in many setups to avoid problems caused by routers 152: that drop ICMP Datagram Too Big messages. Without these messages, 153: the originating machine sends data, it passes the rogue router then 154: hits a machine that has an MTU that is not big enough for the data. 155: Because the IP Don't Fragment option is set, this machine sends an 156: ICMP Datagram Too Big message back to the originator and drops the 157: packet. The rogue router drops the ICMP message and the originator 158: never gets to discover that it must reduce the fragment size or drop 159: the IP Don't Fragment option from its outgoing data. 160: The code is based on tcpmssd wich was written by Ruslan Ermilov 161: <A href="mailto:<ru@FreeBSD.org>">mailto:<ru@FreeBSD.org></A> 162: based on work done by Patrick Bihan-Faou 163: <A href="mailto:<patrick@mindstep.com>">mailto:<patrick@mindstep.com></A>. 164: The default is disable. 165: 166: <dt><code>tee</code><dd>If enabled, a ng_tee(4) node will be inserted 167: into the bundle graph, right after the interface node. The tee node 168: can be useful for debugging or traffic accounting. 169: The default is disable. 170: 171: <dt><code>nat</code><dd>Enable NAT for this bundle. 172: See 173: <A HREF="mpd39.html#nat">nat</A> for more information. 174: The default is disable. 175: 176: <dt><code>netflow-in</code><dd> 177: <dt><code>netflow-out</code><dd> 178: <dt><code>netflow-once</code><dd>If enabled, the bundle will participate in 179: NetFlow generation. See 180: <A HREF="mpd34.html#netflow">netflow</A> 181: for more information. The netflow-out option is like netflow-in, but 182: generates NetFlow data for outgoing packets instead of incoming. 183: If netflow-once enabled - packet will be accounted only once while 184: in kernel. 185: The default is disable. 186: 187: <dt><code>ipacct</code><dd>If enabled, the bundle will participate in IP accounting with ng_ipacct node. 188: See 189: <A HREF="mpd35.html#ipacct">ipacct</A> for more information. 190: The default is disable. 191: 192: </dl> 193:  194: <HR NOSHADE> 195: <A HREF="mpd.html">Mpd 5.7 User Manual</A> 196: : <A HREF="mpd17.html">Configuring Mpd</A> 197: : Interface layer  198: Previous: <A HREF="mpd27.html">IPv6CP layer</A>  199: Next: <A HREF="mpd29.html">Authentication, Authorization and Accounting (AAA)</A> 200: 201: 202: 203: </BODY> 204: </HTML>