Passing Interface Name to Event Script

Rick Solotke RSolotke at
Sat Nov 14 00:40:09 UTC 2009



I have dhcpd running on a router with several network interfaces, all of
which belong to the same subnet.  Because all interfaces belong to the
same subnet, the Linux routing table is ambiguous (an address on the
subnet is reachable via more than one interface).  Consequently, once a
DHCP transaction completes, the router and the new client are unable to
communicate until a static route is added to the router's routing table.
This route specifies the specific IP address of the client and the
interface on which that address is accessible (e.g. route add dev eth0).  If I manually enter the route at the command
line, the router and client are then able to communicate happily.


I'd like to automate this process, so that as soon as the DHCP
transaction occurs, the static route is automatically added.  The dhcpd
COMMIT event seems to be the right place to do this, and I am able to
make the IP address available to the script.  However, I see no way to
make the interface name available to the script.  Without the interface
name, the script is unable to add the static route.


Any suggestions?  dhcpd obviously knows which interface the DHCP
transaction occurred on, but is there any way that information can be
made available to the event script?  If not, does anyone have a
suggestion for another way to accomplish assignment of the static route
upon DHCP completion?


Thanks very much,


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