Ok, here's my problem and some potential solutions. We use static routing
on our Ciscos to get packets from our OSPF backbone to the async
connections on our Portmasters. Unfortunately, this causes problems when
packets are sent to an IP address which is not currently in use. A simple
ping generates a storm of packets as it spins into a tight loop between the
Portmaster and its default gateway.
Our current solution is to configure ofilter for ether0 to permit only
those packets sourced from the async side or from the Portmaster itself.
That effectively disables the ether0-to-ether0 routing which causes the
packet storms.
This solution is sort of awkward, and I think it would hurt performance
if we needed, say, thirty different filter rules.
Is there a better way to handle this right now?
It'd be nice if we could tell a Portmaster not to send packets to its
default route if the packets would go out the same interface on which they
were received.
Another way to do it -- perhaps this will come with OSPF and VLSM? -- would
be to have routes to "all" or "s13" rather than a particular IP address.
Such routes would stay in the table all the time and would be used to
generate ICMP unreachables as necessary. With a higher-than normal
administrative distance, they could be overridden when a connection is
established. Something like
add route 192.168.1.64 255.255.255.224 all 10
and then when 192.168.1.67 comes up on s3, the automatic
192.168.1.67 255.255.255.224 192.168.1.67 HLC 1 ptp3
entry would override the other one. (Disclaimer: not having played with
ComOS 3.5, I have no idea what the actual "add route" syntax and
"show route" display are like -- I just made it up.)
-- Marc Rouleau
VP and Director of Engineering Voice: (812) 479-1700 Fax: (812) 479-3439
World Connection Services, LLC The Home of Evansville Online
http://www.evansville.net