Possible to know my host isn't reachable across router?

On Host A attached to subnet 10.0.1.x, I add an alias IP address
192.168.20.82 using ip addr add , giving:
inet 10.0.1.10/24 brd 10.0.1.255 scope global eth0
inet 192.168.20.82/24 brd 192.168.20.255 scope global eth0

However, the 192.168.x.x ip address cannot be pinged from Host B on the
other side of the router. Is it possible from within a script running
on Host A to determine that 192.168.20.82 cannot be reached from the
other side of the router? Or must the test be done on Host B?


GC

On 22 Jan 2005 08:04:34 -0800, (E-Mail Removed) <(E-Mail Removed)> wrote:
> On Host A attached to subnet 10.0.1.x, I add an alias IP address
> 192.168.20.82 using ip addr add , giving:
> inet 10.0.1.10/24 brd 10.0.1.255 scope global eth0
> inet 192.168.20.82/24 brd 192.168.20.255 scope global eth0
>
> However, the 192.168.x.x ip address cannot be pinged from Host B on the
> other side of the router. Is it possible from within a script running
> on Host A to determine that 192.168.20.82 cannot be reached from the
> other side of the router? Or must the test be done on Host B?

What kind of router? Is the router doing NAT (masquerade), or is it even
aware of the 192.168.20.x alias IP or network on its LAN (does it have
proper route to it)? Does host B know to use router WAN IP as gateway for
192.168.20/24 (or as default gateway assuming that IP range is not in its
LAN).

Does 'ping -I 192.168.20.82 hostB' from hostA work?