Re: arp table - same mac address shows two ip addresses

On 10/18/2018 09:12 AM, Erik Auerswald wrote:
> What I meant was a host configured for network A but connected to 
> network B:
> 
> ES 10.20.30.47/24 <-----> GW Iface 172.16.30.1/24
> 
> The gateway (GW) did have the IP address 10.20.30.1/24 on another 
> interface, and the end-system (ES) used that IP address as its default 
> gateway. ES and GW could ping each other. The GW was a PC with Linux 
> kernel and GNU userland. Thus the "application" on the multi-NIC PC 
> was Linux.
> 
> Just one routing table. A PC with several NICs, GNU/Linux, and 
> ipforwarding acting as a "router".
> 
> In the above mentioned situation, of which I have forgotten most of 
> the details, end-systems that should no longer have been able to reach 
> their old Linux-based default gateway, because IP addresses and VLANs 
> were changed, but the end-systems used the pre-change configuration, 
> still had full network connectivity.

I'll admit that such is a non-intuitive behavior.

However I've learned that such is the expected behavior of a "weak end 
system", which Linux does by default.  I say "by default" because I 
think it's possible to change Linux's behavior.

> When using Linux on a PC with several NICs, expect the unexpected. ;)

Or, change the default so that you get different results.



-- 
Grant. . . .
unix || die