Conference turris::digital_unix

    The outgoing connection simply uses the first IP address
    configured on that network interface (which is called the
    primary IP address).
    
    The alias addresses are not used, and no attempt is made to
    match the destination subnet with one of these aliases to
    avoid routing lookup errors on the return path.
    
    To workaround this problem, you can swap your IP addresses,
    so the alias is the primary and the primary (10.x.x.x) is
    an alias.  Then outgoing connections will always use the
    194.x.x.x address.
    
    Of course, if anyone is relying on seeing 10.x.x.x address,
    then that will suffer the same problems you've seen with using
    the alias.
    
    John
    

Hi John,

Thanks for your answer.
I already surgersted the 'swap addresses' to the customer, but they where
affraid that the same problem would appear on the internel net.

I must say, that I still see the behavior of the UNIX machine as illegal
to how a IP node should behave.

>    The outgoing connection simply uses the first IP address
>    configured on that network interface (which is called the
>    primary IP address).

I think that two nodes on the same IP net, should talk to each other using 
this common IP net.

Anyway,
I will try to se if we can implement a 2 interfase solution.
This should work..... Don't you think ?

			Jan 

    When you use alias for an Interface, the system can use these address
    interchangabally. When two aliases are in different (sub)networks,
    interface route is created for both the (sub)network on the UNIX
    m/c. In your example you will see a route to network 10 and network 194
    (depending on your netmask). When doing that and running routing daemon
    on UNIX m/c, it will advertise route for both network 10 and network
    194 so the normal (non-x.25) router would pick-up and will know both
    network 10 and network 194 exist on the same wire.
    
    However, i'm not sure about Wanrouter, but you need to configure in
    Wanrouter that network 10 and network 194 are on the same wire (that
    generally done uisng IGP protocol RIP via routed/gated).
    
    It's not a IP bug, but artifact of X.25 (NBMA networks including ATM)'s
    -- lack of IP routing support.
    
    --Ajay Kachrani

So a nonrouting-node with 2 addresses on a LAN.

  10.8.41.12
  194.117.116.105

Who is to talk via an other node on the same LAN

  194.117.116.104
  
Can use the source address 10.8.41.12, and send the packet to 194.117.116.104 ?

Well, if it is no bug, it's a 'thin' implementation. ( I think )

In my opinion, if a node in 'IP-net YYY' 
talks to a node in ,IP-net YYY', 
it should use source address 'IP-net YYY'.

			Jan




 

       > Well, if it is no bug, it's a 'thin' implementation. ( I think )
    
    IP aliases are only officially supported within the same subnet,
    which is why using another subnet results in subtle inconsistencies
    which appear broken, depending on your point of view.
    
    If we officially supported aliases in different subnets, this is
    one of the things that would probably be changed, ie. find the best
    match for the outgoing connections.
    
    John
    

    OK, Thank you both for the help.
    
    			Jan