route add -host ... -iface issues

Vladimir Grebenschikov vova at fbsd.ru
Mon Nov 15 10:08:52 PST 2004


В пн, 15/11/2004 в 18:28 +0100, Sławek Żak пишет:
> Hi,
> 
>     I'd like to ask why a static arp entry is added when direct route to host is
>     added like this?
> 
>     route add -host target -iface interface
> 
>     The route(8) manpage says, that such route entry is for hosts directly
>     reachable over interface. But when packets go out on this interface, the MAC
>     address of target host in each packet is set to local MAC for the interface,
>     which effectively stops the target host from receiving the packet.

But anyway, I have question to our routing gurus, why we need install
broken routes in case of ethernet interfaces ? Like:

# route add 172.1.1.1 -iface fxp0
add host 172.1.1.1: gateway fxp0
# netstat -rn | fgrep 172
172.1.1.1          08:00:46:c8:45:b3  UHLS        0        0   fxp0
# ifconfig fxp0 ether
fxp0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
        options=8<VLAN_MTU>
        ether 08:00:46:c8:45:b3
#

Installed routing entry is definitely broken, and can't be used,
probably /sbin/route should add cloning flag automatically when direct
route added for some ethernet (and like) interface ?

I guess it is common mistake.

Also, everyone going to add route-entry via specific MAC address will be
puzzled. I know it is possible, but just now I can't remember how, and
route(8) does not show any light on this question. 

> /S    

-- 
Vladimir B. Grebenchikov
vova at fbsd.ru


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