2 .\" Copyright (c) 2008 The DragonFly Project. All rights reserved.
4 .\" This code is derived from software contributed to The DragonFly Project
5 .\" by Matthew Dillon <dillon@backplane.com>
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21 .\" THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22 .\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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34 .\" $DragonFly: src/usr.sbin/vknetd/vknetd.8,v 1.3 2008/05/31 12:04:15 swildner Exp $
41 .Nd create a bridged network for (typically user-run) vkernels
46 .Op Fl p Ar socket_path
48 .Op Ar address Ns / Ns Ar cidrbits
52 utility creates a virtualized bridged network suitable for vkernel use.
53 The utility was created to simplify
55 operations and to allow user-run
56 vkernels to have access to a network.
57 General use is to specify a large 10-dot network which multiple vkernels are
58 then able to connect to, and backfeed the whole mess to a TAP interface.
62 would make use of the virtualized network by specifying
63 .Fl I Ar /var/run/vknet
67 Any number of vkernels may connect to the virtual network.
70 Implements a simple bridge for all entities connected to it.
72 of MAC addresses is built up (just like an ethernet switch does) and matching
73 packets will be forwarded directly to the proper
75 (connected clients or TAP interface).
76 Unknown MACs will be broadcast.
78 The following options are available:
81 Connect into the bridge and monitor activity.
82 This option currently only monitors broadcast packets.
83 Packets with cached MACs are not monitored.
86 Do not go into the background.
89 Act as a pure bridge and do not try to secure the IP
90 space from host visibility.
91 This is typically used with the
93 option to directly bridge
95 into the host rather than operating it as a separate subnet.
100 will be bridged into the specified bridge.
101 .It Fl p Ar socket_path
102 Specify where to create the unix domain socket in the filesystem space.
103 By default the socket is called
111 will search for an unused TAP interface.
112 .It Ar address Ns / Ns Ar cidrbits
113 When operating in secure mode (which is the default), a CIDR block must be
115 It is optional in unsecure mode.
118 is the address you wish to assign to the TAP
119 interface and will sit on both the host and virtual networks if not bridged.
122 is the number of bits representing the virtual subnet.
124 10.1.0.1/24 places the TAP interface on 10.1.0.1 and gives you an 8 bit
125 subnet capable of handling 254 hosts.
126 An address of 0.0.0.0 is allowed as a special case in secure mode so that
132 .Bl -tag -width ".Pa /var/run/vknet" -compact
134 TAP interface used to route packets from userland providers back into the
136 If not otherwise specified an unused TAP interface will be selected.
137 .It Pa /var/run/vknet
140 sits on waiting for connections.
143 .Dl "vknetd 10.1.0.1/16"
165 command was written by Matthew Dillon and first appeared in
170 defaults to secure mode and will prevent IP spoofing, but the security
171 does not yet handle ARP issues so ARP spoofing can be used to create a
172 denial of service attack on the host network.
175 does not currently implement a timeout for its MAC cache.