Why do packets to 127.255.255.255 cause dial-up?
nik at freebsd.org
Fri Mar 31 00:40:04 BST 2000
On Thu, Mar 30, 2000 at 03:23:15PM +0100, Richard Smith wrote:
> It looks to me that the route to lo0 is 127.0.0.1/32 not 127/8, in which
> case the address 127.255.255.255 will use the default gateway, being
> tun0, QED (smug mode) :-)
Ah, indeed. I hate it when I can't see the wood for the trees. Nothing
route add -net 127 lo0
can't solve. This then gives the expected:
Destination Gateway Flags Refs Use Netif Expire
default 22.214.171.124 UGSc 20 668 tun0
127 lo0 USc 0 0 lo0
127.0.0.1 127.0.0.1 UH 0 0 lo0
lines. And no packets wending their way down tun0 by mistake.
The more interesting question is why is this happening? The only other
IP enabled system I have to hand is Win98 (I know, I know), and a quick
"route print" shows that the 127.0.0.1 route has a /8 netmask rather than
I've got the usual /etc/hosts,
127.0.0.1 localhost.ngo.org.uk localhost
entry, and a local nameserver, which resolves "localhost" to 127.0.0.1.
It's my understanding that 127/8 is the 'local net', and that packets to
any 127/8 address should go via the loopback interface. That being the
default, shouldn't a 127/8 route automatically exist to lo0?
If it should, is it just my system that's misconfigured, and does
everybody else have a 127/8 route on their systems?
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