>>>>> "gt" == Greg Troxel <gdt%ir.bbn.com@localhost> writes: gt> It's basically wrong to expect NetBSD to arp when sending a gt> packet other than on the subnet configured with that prefix gt> using a cloning route. ARP is triggered by a packet hitting gt> the cloning route. The problem is that the route added by ARP needs to be more specific than the cloning route, so it's impossible to add a /32 cloning route. The cloning route single-table thing is kind of a neat hack, but it's not fully general. Cisco handles the corner cases better, and you can have two devices communicating which don't share a subnet: router a -----8<----- interface FastEthernet0/0 ip address 126.96.36.199 255.255.255.254 ip route 188.8.131.52 255.255.255.255 FastEthernet0/0 -----8<----- router b -----8<----- interface FastEthernet0/0 ip address 184.108.40.206 255.255.255.254 ip route 220.127.116.11 255.255.255.255 FastEthernet0/0 -----8<----- These two will have full connectivity, without any static ARP, which is impossible on BSD. But even Cisco isn't fully general because it seems you can't assign a /32 address to an Ethernet interface. I have at least two other problems with cloning/cloned routes. I've also had problems on OpenBSD when I move wired<->wireless (two different subnets), there's some kind of cloned /32 pointing at the old default route which doesn't get cleared. Sometimes I have to: # pkill dhclient # dhclient em0 # ssh 18.104.22.168 [waits] ^C # route delete 22.214.171.124 delete host 126.96.36.199 # route delete 188.8.131.52 route: writing to routing socket: No such process delete host 184.108.40.206: not in table # ssh 220.127.116.11 Password: Then there's also the problem you mentioned years ago that interfaces with no link indication or even 'ifconfig down' interfaces, so long as they've an IP and subnet configured onto them, will still add their implicit direct route for that subnet and prevent you from reaching the same host through a different interface. This also bites me with moving wired/wireless. You've more flexibility if the cloning route and all its children were removed on link-down or 'ifconfig down' as it is on Cisco or Juniper or EnTee, but I expect nobody wants to change it because the new more-correct behavior surprised and annoyed them, once, the first time they saw it on Cisco five years ago before they learned to use loopback interfaces for that stuff.
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