OT: cannot ping remote machine

[Timothy Murphy]

I can access a remote computer (in Italy) with openvpn,
but I cannot ping its external address,
or ssh to this address.

I can login with ssh to the openvpn address 192.168.5.22 ,
and then I get the external address with
------------------------
[tim at alfred ~]$ lynx -dump "http://checkip.dyndns.org"

   Current IP Address: 79.46.130.4

[tim at alfred ~]$ ping -c1 79.46.130.4
PING 79.46.130.4 (79.46.130.4) 56(84) bytes of data.
64 bytes from 79.46.130.4: icmp_seq=1 ttl=253 time=1.14 ms
------------------------

As shown, I can ping this address from the remote machine.
However, I cannot ping it from my home machine (in Ireland).

I'm using a Billion modem/router in Italy;
I'm not sure if the problem lies with this?
Or if some server along the way refuses to allow pings?

When I run "traceroute 79.46.130.4" from Ireland
I get as far as Milan (in Italy) but then just get *** .

The issue is rather academic, as I can (and do) use openvpn.
But I have a (free) DynDNS account, which gets the IP address OK,
and I would quite like to be able to access the machine that way.

Any elucidation gratefully received,
and apologies if this is too OT.

-- 
Timothy Murphy  
e-mail: gayleard /at/ eircom.net
tel: +353-86-2336090, +353-1-2842366
s-mail: School of Mathematics, Trinity College, Dublin 2, Ireland