[LARTC] Re[4]: local address routeable?

[LARTC] Re[4]: local address routeable?

[Christian Stuellenberg]

>>>>> "Christian" = Christian Stuellenberg <christian_stuellenberg@web.de> writes:
>>>>> "Julian" = Julian Anastasov <ja@ssi.bg> writes:
Hello,

    Christian> If traffic from zone MASQ is addressed to one of the
    Christian> external internet addresses of one of the zone GOOD or
    Christian> DMZ, then it will currently get routed directly at
    Christian> HOST.  It is intended, that this direct routing is not
    Christian> done, but instead ALL traffic from zone MASQ becomes
    Christian> masqueraded out over the dynamic PPP connection to the
    Christian> internet, comes back over the CISCO line to HOST, then
    Christian> gets routed to the extern destination IP (in zone GOOD
    Christian> or DMZ) and when the reply from there comes back again
    Christian> to HOST, it should get routed over the CISCO internet
    Christian> connection and then back over the dynamic PPP
    Christian> connection, demasqueraded, and at last delivered to the
    Christian> original source in zone MASQ.

    Christian> This works up to the point, where the reply comes back
    Christian> to HOST.  Now I'm not able to tell HOST, that this
    Christian> reply should again routed out to the internet over the
    Christian> CISCO line and only demasqueraded if it comes in over
    Christian> the PPP connection (btw.  the demasquerading does also
    Christian> not occur if the reply gets not routed; I assume, this
    Christian> is because the masquerding tables are waiting for a
    Christian> packet that comes in over the PPP connection and not on
    Christian> IF0 or IF1).

    Julian> 	I think, I understand the setup. I'm still wondering
    Julian> what is the end goal. I can only speculate:

    Julian> Assumption 1. Hosts from GOOD want to see client from
    Julian> DynIP, not from a.b.c.62. The solution: use SNAT with
    Julian> saddr=DynIP when talking to GOOD because the default
    Julian> masquerade action is to use a.b.c.62 which is recommended
    Julian> from the routing. I assume GOOD and DMZ do not care how
    Julian> the packet with saddr=DynIP appeared as long as it looks
    Julian> as expected?

    Julian> 2. For some reason (even by introducing security problems)
    Julian> you want packets with saddr=DynIP to walk the external
    Julian> path and to reach GOOD. Is it needed? Is there a problem
    Julian> with the above solution in #1?

I really want the long path, so that a client in zone MASQ can test,
whether both uplinks to the internet work correctly.  Not only to test
the links, but also to provide a way, that a client in zone MASQ looks
like any other (actually masqueraded) client in the world.  We
would'nt achieve that, if the routing from a client in zone MASQ takes
directly place on HOST.

Regards,
Christian

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