@node Zebra
@comment  node-name,  next,  previous,  up
@chapter Zebra

@c SYNOPSIS
@command{zebra} is an IP routing manager.  It provides kernel routing
table updates, interface lookups, and redistribution of routes between
different routing protocols.

@menu
* Invoking zebra::              Running the program
* Interface Commands::          Commands for zebra interfaces
* Static Route Commands::       Commands for adding static routes
* zebra Terminal Mode Commands::  Commands for zebra's VTY
@end menu


@node Invoking zebra, Interface Commands, Zebra, Zebra
@comment  node-name,  next,  previous,  up
@section Invoking zebra

Besides the common invocation options (@pxref{Common Invocation Options}), the
@command{zebra} specific invocation options are listed below.

@table @samp
@item -b
@itemx --batch
Runs in batch mode.  @command{zebra} parses configuration file and terminates
immediately.

@item -k
@itemx --keep_kernel
When zebra starts up, don't delete old self inserted routes.

@item -l
@itemx --log_mode
Set verbose logging on.

@item -r
@itemx --retain
When program terminates, retain routes added by zebra.

@end table

@node Interface Commands, Static Route Commands, Invoking zebra, Zebra
@comment  node-name,  next,  previous,  up
@section Interface Commands

@deffn Command {interface @var{ifname}} {}
@end deffn

@deffn {Interface Command} {shutdown} {}
@deffnx {Interface Command} {no shutdown} {}
Up or down the current interface.
@end deffn

@deffn {Interface Command} {ip address @var{address/prefix}} {}
@deffnx {Interface Command} {ip6 address @var{address/prefix}} {}
@deffnx {Interface Command} {no ip address @var{address/prefix}} {}
@deffnx {Interface Command} {no ip6 address @var{address/prefix}} {}
Set the IPv4 or IPv6 address/prefix for the interface.
@end deffn

@deffn {Interface Command} {ip address @var{address/prefix} secondary} {}
@deffnx {Interface Command} {no ip address @var{address/prefix} secondary} {}
Set the secondary flag for this address. This causes ospfd to not treat the
address as a distinct subnet.
@end deffn

@deffn {Interface Command} {description @var{description} ...} {}
Set description for the interface.
@end deffn

@deffn {Interface Command} {multicast} {}
@deffnx {Interface Command} {no multicast} {}
Enable or disables multicast flag for the interface.
@end deffn

@deffn {Interface Command} {bandwidth <1-10000000>} {}
@deffnx {Interface Command} {no bandwidth <1-10000000>} {}
Set bandwidth value of the interface in kilobits/sec.  This is for 
calculating OSPF cost. This command does not affect the actual device 
configuration.
@end deffn

@deffn {Interface Command} {link-detect} {}
@deffnx {Interface Command} {no link-detect} {}
Enable/disable link-detect on platforms which support this. Currently 
only linux and with certain drivers - those which properly support the 
IFF_RUNNING flag.
@end deffn

@node Static Route Commands, zebra Terminal Mode Commands, Interface Commands, Zebra
@comment  node-name,  next,  previous,  up
@section Static Route Commands

Static routing is a very fundamental feature of routing technology.  It
defines static prefix and gateway.

@deffn Command {ip route @var{network} @var{gateway}} {}
@var{network} is destination prefix with format of A.B.C.D/M.
@var{gateway} is gateway for the prefix.  When @var{gateway} is
A.B.C.D format.  It is taken as a IPv4 address gateway.  Otherwise it
is treated as an interface name. If the interface name is @var{null0} then
zebra installs a blackhole route.

@example
ip route 10.0.0.0/8 10.0.0.2
ip route 10.0.0.0/8 ppp0
ip route 10.0.0.0/8 null0
@end example

First example defines 10.0.0.0/8 static route with gateway 10.0.0.2.
Second one defines the same prefix but with gateway to interface ppp0. The
third install a blackhole route.
@end deffn

@deffn Command {ip route @var{network} @var{netmask} @var{gateway}} {}
This is alternate version of above command.  When @var{network} is
A.B.C.D format, user must define @var{netmask} value with A.B.C.D
format.  @var{gateway} is same option as above command

@example
ip route 10.0.0.0 255.255.255.0 10.0.0.2
ip route 10.0.0.0 255.255.255.0 ppp0
ip route 10.0.0.0 255.255.255.0 null0
@end example

These statements are equivalent to those in the previous example.
@end deffn

@deffn Command {ip route @var{network} @var{gateway} @var{distance}} {}
Installs the route with the specified distance.
@end deffn

Multiple nexthop static route

@example
ip route 10.0.0.1/32 10.0.0.2
ip route 10.0.0.1/32 10.0.0.3
ip route 10.0.0.1/32 eth0
@end example

If there is no route to 10.0.0.2 and 10.0.0.3, and interface eth0
is reachable, then the last route is installed into the kernel.

If zebra has been compiled with multipath support, and both 10.0.0.2 and
10.0.0.3 are reachable, zebra will install a multipath route via both
nexthops, if the platform supports this.

@example
zebra> show ip route
S>  10.0.0.1/32 [1/0] via 10.0.0.2 inactive
                      via 10.0.0.3 inactive
  *                   is directly connected, eth0
@end example

@example
ip route 10.0.0.0/8 10.0.0.2
ip route 10.0.0.0/8 10.0.0.3
ip route 10.0.0.0/8 null0 255
@end example

This will install a multihop route via the specified next-hops if they are
reachable, as well as a high-metric blackhole route, which can be useful to
prevent traffic destined for a prefix to match less-specific routes (eg
default) should the specified gateways not be reachable. Eg:

@example
zebra> show ip route 10.0.0.0/8             
Routing entry for 10.0.0.0/8
  Known via "static", distance 1, metric 0
    10.0.0.2 inactive
    10.0.0.3 inactive

Routing entry for 10.0.0.0/8
  Known via "static", distance 255, metric 0
    directly connected, Null0
@end example

@deffn Command {ipv6 route @var{network} @var{gateway}} {}
@deffnx Command {ipv6 route @var{network} @var{gateway} @var{distance}} {}
These behave similarly to their ipv4 counterparts.
@end deffn


@deffn Command {table @var{tableno}} {}
Select the primary kernel routing table to be used.  This only works
for kernels supporting multiple routing tables (like GNU/Linux 2.2.x
and later).  After setting @var{tableno} with this command, 
static routes defined after this are added to the specified table.
@end deffn

@node zebra Terminal Mode Commands,  , Static Route Commands, Zebra
@comment  node-name,  next,  previous,  up
@section zebra Terminal Mode Commands

@deffn Command {show ip route} {}
Display current routes which zebra holds in its database.

@example
@group
Router# show ip route 
Codes: K - kernel route, C - connected, S - static, R - RIP, 
       B - BGP * - FIB route.

K* 0.0.0.0/0              203.181.89.241
S  0.0.0.0/0              203.181.89.1
C* 127.0.0.0/8            lo
C* 203.181.89.240/28      eth0
@end group
@end example
@end deffn

@deffn Command {show ipv6 route} {}
@end deffn

@deffn Command {show interface} {}
@end deffn

@deffn Command {show ipforward} {}
Display whether the host's IP forwarding function is enabled or not.
Almost any UNIX kernel can be configured with IP forwarding disabled.
If so, the box can't work as a router.
@end deffn

@deffn Command {show ipv6forward} {}
Display whether the host's IP v6 forwarding is enabled or not.
@end deffn