REPLY: 2:5020/545 61da7f32   
   MSGID: 2:5005/49 61da88e0   
   CHRS: CP866 2   
   TZUTC: 0700   
   TID: hpt/fbsd 1.9.0-cur 2019-12-05   
   Dear Alexey,   
      
   09 Jan 22 09:21, you wrote to me:   
      
    TK>>>>> I have a wireguard server running in my VPS (Ubuntu 20.04.3   
    TK>>>>> LTS). It is using a /112 of /64 for it's clients.   
    VS>>>> Do you mean to say you can have a /64 network on your VPS' main   
    VS>>>> interface and at the same time a /112 from the *same* *network*   
    VS>>>> on a wg0 interface? Is this even permitted by the OS?   
    AV>>> Yes - at least properly configured Linux allows this.   
    VS>> What do you mean by "properly configured"? You mean the   
    VS>> out-of-the-box configuration still does not allow this?   
      
    AV> Obviously.   
      
   What do you need to configure to enable this behaviour on Linux?   
      
    VS>> A Cisco router would not allow the same L2 network on two   
    VS>> different L3 interfaces IMHO, even if one of the prefixes is more   
    VS>> specific.   
      
    AV> That's a limitation of BSD-style IP stack.   
      
   Interestingly enough, FreeBSD 12.3 has just let me do exactly that (sorry, an   
   IPv4 example), without any additional configuration. The world is full of   
   wonders:   
      
   root@vas:~ # apply ifconfig lo{2,3}   
   lo2: flags=8049 metric 0 mtu 16384   
           options=680003   
           inet 192.168.13.1/24   
           groups: lo   
           nd6 options=29   
   lo3: flags=8049 metric 0 mtu 16384   
           options=680003   
           inet 192.168.13.129/25   
           groups: lo   
           nd6 options=29   
   root@vas:~ #   
   root@vas:~ # apply 'route get ' 192.168.13.2 192.168.13.200   
      route to: 192.168.13.2   
   destination: 192.168.13.0   
          mask: 255.255.255.0   
           fib: 0   
     interface: lo2   
         flags:    
    recvpipe  sendpipe  ssthresh  rtt,msec    mtu        weight    expire   
          0         0         0         0     16384         1         0   
      
      route to: 192.168.13.200   
   destination: 192.168.13.128   
          mask: 255.255.255.128   
           fib: 0   
     interface: lo3   
         flags:    
    recvpipe  sendpipe  ssthresh  rtt,msec    mtu        weight    expire   
          0         0         0         0     16384         1         0   
   root@vas:~ #   
      
      
      
   Victor Sudakov, VAS4-RIPE, VAS47-RIPN   
   --- GoldED+/BSD 1.1.5-b20170303-b20170303   
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