Re: Confirm: letting certain packages pass through un-natted

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Hello!

>>    +---------------+
>>    |     modem     |
>>    | (192.168.1.1) |
>>    +---------------+
>>            |
>>   +-----------------+
>>   |       ppp0      |
>>   |        |        |
>>   |  ...1.2 (eth0)  |
>>   |        |        |eth1
>>   |           ...2.1|-----192.168.2.0/24
>>   |     Firewall    |
>>   +-----------------+
>
> [SNIP]
>
>
>>Destination Gateway    Genmask      Iface
>>192.168.1.0    *    255.255.255.0   eth0
>>192.168.2.0    *    255.255.255.0   eth1
>>default       xxx   0.0.0.0         ppp0
>
>
> [Rest snipped - probably not relevant]
>
> The only thing I can think of, is that pppd causes the problem.
> I think the following happens:
>
> 2.2 sends to 1.1
> Firewall receives on 2.1
> According to routing table firewall tries to send out on eth0
> But eth0 is now owned by pppd
> And pppd doesn't know about 1.1, he only knows about default
> gateway xxx
>
> As already said - this may be totally wrong (someone correct
> me please).
>
> I bet if you stop pppd, 2.2 can connect to 1.1 without any firewall
> rules (as long as the policies are ACCEPT and default gateway on 2.2
> points to 2.1). If this is true, the question is how to persuade
> pppd to deliver to 1.1. Sorry, I can't help you - may be
> somebody can jump in.

Hmmm... unfortunately, this does not seem to be the case...

I say this for two reasons:

 1. I can still connect to 192.168.1.1 from 192.168.2.1
 2. Even when I bring down ppp0, I still can't reach
    192.168.1.1 from anywhere other than the machine
    I mention in (1)

Unless, I didn't do the right thing. I simply did:

 # ifconfig ppp0 down

Is this sufficient?


Thanks again!!

Dave



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