Hi, as written in PM my submitted script was an very ancient version. Find attached the current Version. What I did there is if netmask is /32 then set a device-route for the gateway-ip. Sorry for confusion. BR Jens On 05.06.2012 18:50, Michael Tokarev wrote: > On 05.06.2012 20:41, Jens Ott - Profitbricks wrote: >> Michael >  >>> For now I see another _possible_ issue, which needs >>> to be verified in d-i: this is the place which adds >>> routes. Neither debian default.script nor your script >>> is able to add routes: >>> >>> # busybox ip r add 10.255.0.0/28 via 192.168.77.11 dev dummy0 >>> ip: RTNETLINK answers: No such process >> >> That can't work. > > Sure, because the "gateway" 192.168.77.11 isn't reachable > when the netmask is /32, this is exactly what I described > (quoted below). > >> That's why my script sets the routers-variable to $ip >> when netmask is "255.255.255.255". > > And this does not work to. I think you had a typo there. > See: > > [ "$subnet" = "255.255.255.255" ] && routers=$ip > case "$1" in > renew|bound) > if [ -n "$router" ] ; then > for i in $router ; do > echo "Adding router $i" > route add default gw $i dev $interface metric $((metric++)) > done > fi > .. > > > Note you're setting "routeS" while use "routeR". > > This is why it should not work exactly the same way > as current busybox's version! > >> Somewhere in ARP-RFC it is defined that a router shall respond to >> WHO-HAS requests where requester and sender is the same address. So you >> actually set default-route to the assigned IP on /32-Assignments. > > Well. In this case, the DHCP server should just set router > correctly, to be the same as client address, everything will > Just Work (tm). > > This is a good piece of information, and why I asked for a > reproducer -- it didn't occur to me to use the same IP for > router and client's own ip address, even if I know it might > work exactly the way you describe by sending an ARP for everyhing. > > The same can also be achieved by using not own's IP address > but all zeros, like, > > ip route add default via 0.0.0.0 dev eth0 > > and this is even more correct, I think, this is equivalent > of not specifying "via" at all. Again, this can be set in > the DHCP server. > > I thought about a different case, when you actually specify > some non-dummy gateway, it is not this case... > > So, I guess, nothing should be fixed on the busybox/debian > side, do you not agree? :) > > Thank you! > > /mjt > >>> The same happens when using route(8) utility. For this >>> to work, two routes should be added: first to the gateway >>> host, without the "via" part: >>> >>> # busybox ip r add 192.168.77.11 dev dummy0 >>> >>> and second is the actual default (or whatever) route going >>> via that gateway, the regular way: >>> >>> # busybox ip r add 10.255.0.0/28 via 192.168.77.11 >>> >>> ("dev" is optional here, just like for the regular case). >>> >>> Alternative is to use the keyword "onlink": >>> >>> # ip r add 10.255.0.0/28 via 192.168.77.11 dev dummy0 onlink >>> >>> but this does not work with busybox (yet).