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mpd 5.9

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 5.9 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">IP Control Protocol (IPCP) layer</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: <pre> 36: %% expands to single % sign; 37: %a for interface local address; 38: %A for peer local address; 39: %i for system interface index; 40: %I for interface name; 41: %l for name of bundle's first link 42: %M for peer MAC address of bundle's first link 43: %o for local outer ("physical") address of bundle's first link 44: %O for peer outer ("physical") address of bundle's first link 45: %P for peer outer ("physical") port of bundle's first link 46: %S for interface status (DoD/UP/DOWN) 47: %t for type of bundle's first link (pppoe, pptp, l2tp etc.) 48: %u for self auth name (or dash if self auth name not used) 49: %U for peer auth name (or dash if peer has not authenticated) 50: </pre> 51:  52: 53: <dt><code>set iface group [ group ]</code><dd>This command add interface to specific group. 54: 55: <dt><code>set iface addrs [!]local-ip [!]remote-ip</code><dd>This command is usually required when dial-on-demand is enabled. 56: Normally, mpd configures the interface with the IP addresses that 57: were negotiated when connecting the link. Since dial-on-demand 58: configures the interface before actually connecting, mpd has to be 59: told initial local and remote IP addresses to give the interface. 60: These addresses do not have to correspond to the ``real'' ones; in 61: fact, both addresses can be completely fictional. If and when 62: different addresses are negotiated later, mpd will automatically 63: renumber the interface and adjust the routes. 64: Also this command may be used to force specified addresses usage 65: instead of negotiated ones. It may be useful in some specific cases, 66: for example, to avoid routing loop with misconfigured PPTP server. 67: In such case '!' mark specifies IPs to be forced. 68: 69: <dt><code>set iface route address[/width]</code><dd>This command associates a route with the bundle. Whenever the 70: interface is configured up, all associated routes are added. 71: A route of <code>default</code> indicates the default route. 72: Otherwise, the route is a network address with optional netmask 73: width (e.g., <code>192.168.1.0/24</code>). If the netmask 74: width is omitted, a single host route is assumed (i.e., a width 75: of 32). 76: Routes are automatically removed when the interface is brought down. 77: 78: <dt><code>set iface mtu value [ override ]</code><dd>Without optional keyword <code>override</code>, this command 79: sets an upper bound on the MTU that will be configured 80: on the interface when the bundle comes up. 81: This value is not used at all during link negotiation; there are 82: separate bundle and link commands for configuring that. 83: Even if a higher bundle MTU is negotiated, this limit will still apply. 84: This command is useful when you want to manually restrict the MTU 85: of the interface for other reasons, e.g., if you're also doing IPSec. 86: The default is 1500. 87: Optional keyword <code>override</code> allows you to override 88: the result of link negotiation and set interface MTU to specified value. 89: Such override can violate RFC 1661, so use with caution and at your own risk. 90: This is useful when you deal with broken PPP peer negotiating too low value 91: while higher MTU is known to work. 92: 93: <dt><code>set iface idle seconds</code><dd>Sets the idle timeout value for the bundle. If no incoming or 94: outgoing packets are transmitted for <code>seconds</code> 95: seconds, the connection is brought down. An idle timeout of 96: zero disables this feature. 97: When the idle timeout occurs, if the dial-on-demand option is 98: enabled, mpd goes back into dial-on-demand mode. Otherwise, the 99: interface is brought down and all associated routes removed. 100: The default is 0. 101: 102: <dt><code>set iface session seconds</code><dd>Sets the session timeout value for the bundle. An session timeout of 103: zero disables this feature. 104: The default is 0. 105: 106: <dt><code>set iface up-script script </code><dd> 107: <dt><code>set iface down-script script </code><dd> 108: Mpd can optionally run a user program every time one of network 109: protocols (IPCP/IPv6CP) at the interface is brought up or down. 110: The <code>up-script</code> is called like this: 111: <blockquote><code> 112: <code>script interface proto local-ip remote-ip authname [ dns1 server-ip ] [ dns2 server-ip ] 113: peer-address</code> 114: </code></blockquote> 115:  116: If up-script exit status is not 0, mpd will kill respective protocol. 117: The <code>down-script</code> is called like this: 118: <blockquote><code> 119: <code>script interface proto local-ip remote-ip authname peer-address</code> 120: </code></blockquote> 121:  122: 123: <dt><code>set iface enable option ...  124: set iface disable option ...</code><dd>Enable and disable the various interface layer options for the bundle. 125: 126: </dl> 127:  128: 129: The options available at the interface layer are: 130:  131: <dl> 132: 133: <dt><code>on-demand</code><dd>This option causes the interface to operate in dial-on-demand mode, 134: allowing you to have a ``virtual full time'' connection. 135: An OPEN event causes the interface to be configured, but the actual 136: connection of the link is delayed until qualifying outgoing traffic 137: is detected. Moreover, after an idle timeout, the interface is not 138: brought down; further traffic will bring the link back up again. 139: The default is disable. 140: 141: <dt><code>proxy-arp</code><dd>When this option is enabled, if after link negotiation the peer's 142: IP address is determined to lie on a local subnet, then mpd will 143: arrange for the local machine to install a proxy ARP entry for 144: the remote machine's IP address. 145: For example, suppose the local machine lies on a LAN with address 146: 192.168.1.10, and another machine will be connecting via mpd 147: and using the LAN address 192.168.1.20. Then these commands would 148: set up proxy ARP for the remote machine: 149: <blockquote><code> 150: <code>set iface enable proxy-arp 151: set ipcp ranges 192.168.1.10/32 192.168.1.20/32</code> 152: </code></blockquote> 153:  154: The default is disable. 155: 156: <dt><code>keep-timeout</code><dd>When this option is enabled, we are not clear ``session timeout'' 157: counter. This is useful together with CoA requests. 158: The default is disable. 159: 160: <dt><code>tcpmssfix</code><dd>This option causes mpd to adjust incoming and outgoing TCP SYN 161: segments so that the requested maximum segment size is not greater 162: than the amount allowed by the interface MTU. 163: This is necessary in many setups to avoid problems caused by routers 164: that drop ICMP Datagram Too Big messages. Without these messages, 165: the originating machine sends data, it passes the rogue router then 166: hits a machine that has an MTU that is not big enough for the data. 167: Because the IP Don't Fragment option is set, this machine sends an 168: ICMP Datagram Too Big message back to the originator and drops the 169: packet. The rogue router drops the ICMP message and the originator 170: never gets to discover that it must reduce the fragment size or drop 171: the IP Don't Fragment option from its outgoing data. 172: The code is based on tcpmssd wich was written by Ruslan Ermilov 173: <A href="mailto:<ru@FreeBSD.org>"><ru@FreeBSD.org></A> 174: based on work done by Patrick Bihan-Faou 175: <A href="mailto:<patrick@mindstep.com>"><patrick@mindstep.com></A>. 176: The default is disable. 177: 178: <dt><code>tee</code><dd>If enabled, a ng_tee(4) node will be inserted 179: into the bundle graph, right after the interface node. The tee node 180: can be useful for debugging or traffic accounting. 181: The default is disable. 182: 183: <dt><code>nat</code><dd>Enable NAT for this bundle. 184: See 185: <A HREF="mpd39.html#nat">the NAT chapter</A> for more information. 186: The default is disable. 187: 188: <dt><code>netflow-in</code><dd> 189: <dt><code>netflow-out</code><dd> 190: <dt><code>netflow-once</code><dd>If enabled, the bundle will participate in 191: NetFlow generation. See 192: <A HREF="mpd34.html#netflow">the NetFlow chapter</A> 193: for more information. The netflow-out option is like netflow-in, but 194: generates NetFlow data for outgoing packets instead of incoming. 195: If netflow-once enabled - packet will be accounted only once while 196: in kernel. 197: The default is disable. 198: 199: <dt><code>ipacct</code><dd>If enabled, the bundle will participate in IP accounting with ng_ipacct node. 200: See 201: <A HREF="mpd35.html#ipacct">the IP Accounting chapter</A> for more information. 202: The default is disable. 203: 204: </dl> 205:  206: <HR NOSHADE> 207: <A HREF="mpd.html">Mpd 5.9 User Manual</A> 208: : <A HREF="mpd17.html">Configuring Mpd</A> 209: : Interface layer  210: Previous: <A HREF="mpd27.html">IPv6CP layer</A>  211: Next: <A HREF="mpd29.html">Authentication, Authorization and Accounting (AAA)</A> 212: 213: 214: 215: </BODY> 216: </HTML>