ipconfig, rip, linklocal, ipv6on – Internet configuration and routing

ip/ipconfig [–6DGNOPdnpruX] [–b baud] [–c ctl] [–g gateway] [–h host] [–m mtu] [–o dhcp–opt] [–x netmtpt] [ type [ device ]] [verb] [ local [ mask [ remote [ file–server [ auth ]]]]]

ip/rip [–bdr] [–x netmtpt]

ip/linklocal [ –t gwipv4 ] mac ...

ipv6on [ netmtpt ndbfile ]

Ipconfig binds a device interface (default /net/ether0) to a mounted IP stack (default /net) and configures the interface with a local address and optionally a mask, a remote address, a file server and an authentication server address. The addresses can be specified in the command line or obtained via DHCP. If DHCP is requested, it will also obtain the addresses of DNS servers, NTP servers, gateways, a Plan 9 file server, and a Plan 9 authentication server. If this is the first non–loopback interface on the IP stack, the information will be written to /net/ndb in the form of an ndb(8) entry.

Type may be ether, ppp, pkt, or loopback. The pkt interface passes all IP packets to and from a user program. For ppp the device can be any byte stream device.

The verb (default add) determines the action performed. The usual verbs are:
add      if the device is not bound to the IP stack, bind it. Add the given local address, mask, and remote address to the interface. An interface may have multiple addresses.
remove   remove the address from the device interface.
unbind   unbind the device interface and all its addresses from the IP stack.

The IPv6–specific verbs, which take different arguments, are:
add6 prefix pfx–len onlink auto validlt preflt
sets the named IPv6 parameters; see ip(3) for more detail.
ra6 [ keyword value ] ...
sets IPv6 router advertisement parameter keyword's value. See ip(3) for more detail. Setting recvra non–zero also forks a process to receive and process router advertisements. Setting sendra non–zero also enables IP routing on the interface, forks a process to send router advertisements, and if no recvra process is running, forks one.

The options are:
6   if adding an address (the default action), add the IPv6 link–local address.
b   the baud rate to use on a serial line when configuring PPP.
c   write the control string ctl to the ethernet device control file before starting to configure it. May be repeated to specify multiple control writes.
d   use DHCP to determine any unspecified configuration parameters.
D   turn on debugging.
g   the default gateway.
G   use only generic DHCP options. Without this option, ipconfig adds to requests a Vendor Class option with value plan9_$cputype and also requests vendor specific options 128 and 129 which we interpret as the Plan 9 file server and auth server. Replies to these options contain a list of IP addresses for possible
file servers and auth servers.
h   the hostname to add to DHCP requests. Some DHCP servers, such as the one used by Comcast, will not respond unless a correct hostname is in the request.
m   the maximum IP packet size to use on this interface.
n   determine parameters but don't configure the interface.
N   look in /lib/ndb for the IP parameters. This only works if the interface is an ethernet. It uses the ethernet address to find a matching entry.
O   addresses specified on the command line override those obtained via DHCP. A command line address of 0 implies no override.
p   write configuration information to /net/ndb, even if other network interfaces are already configured
P   do not write configuration information to /net/ndb, even if this is the first network interface to be configured
r   by default, ipconfig exits after trying DHCP for 15 seconds with no answer. This option directs ipconfig instead to fork a background process that keeps trying forever.
u   disable IPv6 duplicate discovery detection, which removes any existing ARP table entry for one of our IPv6 addresses before adding new ones.
x   use the IP stack mounted at netmtpt instead of at /net.
X   don't fork a process to keep the DHCP lease alive.
o   adds dhcpoption to the list of paramters requested of the DHCP server. The result will appear in /net/ndb should this be the first interface. The known options are:

arptimeout,    baddr,    bflen,    bootfile,    clientid,    cookie,    discovermask,    discoverrouter,    dns,    dom,    dumpfile,    etherencap,    extpath,    finger,    homeagent,    impress,    ipaddr,    ipforward,    ipgw,    ipmask,    irc,    lease,    log,    lpr, maxdatagram,    maxmsg,    message,    mtu,    name,    netbiosdds,    netbiosns,    netbiosscope,    netbiostype,    ni,    nisdomain,    nisplus,    nisplusdomain,    nntp,    nonlocal,    ntp,    overload,    params,    pathplateau,    pathtimeout,    policyfilter, pop3, rebindingtime, renewaltime, rl, rootpath, rs, serverid, smtp, st, staticroutes, stdar, subnetslocal, supplymask, swap, sys, tcpka, tcpkag, tcpttl, tftp, time, timeoff, trailerencap, ttl, type, vendorclass, www, xdispmanager, xfont
The options ipmask, ipgw, dns, sys, and ntp are always requested.

If DHCP is requested, a process is forked off to renew the lease before it runs out. If the lease does run out, this process will remove any configured addresses from the interface.

Rip runs the routing protocol RIP. It listens for RIP packets on connected networks and updates the kernel routing tables. The options are:
b   broadcasts routing information onto the networks.
n   gathers routing information but doesn't write to the route table. This is useful with –d to debug a network.
x   use the IP stack mounted at netmtpt instead of at /net.
d   turn on (voluminous) debugging.

Linklocal prints the IPv6 EUI–64–based link–local address derived from the given mac address. Given –t, linklocal instead prints the 6to4 EUI–64–based IPv6 address derived from mac and 6to4 gateway gwipv4.

Ipv6on uses the network database at ndbfile to configure the network mounted on netmtpt with an IPv6 link–local address (derived from its MAC address) and an IPv6 global address, either from an ipv6 attribute for $sysname or the interface's MAC address, if present, or via stateless address autoconfiguration. It also attempts to add a default IPv6 route from a router advertisement.

Configure Ethernet 0 as the primary IP interface. Get all addresses via DHCP. Start up a connection server and DNS resolver for this IP stack.
% bind –b '#l0' /net
% bind –a '#I0' /net
% ip/ipconfig
% ndb/cs
% ndb/dns –r

Add a second address to the stack.
% ip/ipconfig ether /net/ether0 add

At Bell Labs, our primary IP stack is always to the company's internal firewall–protected network. The following creates an external IP stack to directly access the outside Internet. Note that the connection server uses a different set of ndb files. This prevents us from confusing inside and outside name/address bindings.
% bind –b '#l1' /net.alt
% bind –b '#I1' /net.alt
% ip/ipconfig –x /net.alt –g ether /net.alt/ether1\
% ndb/cs –x /net.alt –f /lib/ndb/external
% ndb/dns –sx /net.alt –f /lib/ndb/external
% aux/listen –d /rc/bin/service.alt /net.alt/tcp

Get all addresses via DHCP. Configure the IPv6 link–local address automatically and listen for router announcements.
ip/ipconfig –6
ip/ipconfig ra6 recvra 1



ether(3), ip(3), loopback(3), ndb(6), 6in4(8), dhcpd(8), ppp(8)
/lib/rfc/rfc2373 for IPv6's modified EUI–64

Currently, ipv6on relies for SLAAC on each ndb ipnet declaration containing an ipv6pfx attribute. This should be replaced by a router advertisement prefix.
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