forwarding/routing traffic (+nat) to gw in a custom routing table

forwarding/routing traffic (+nat) to gw in a custom routing table

[Marc Roos]

I have two interfaces:
eth0 192.168.122.2
eth1 1.1.1.10

I have a routing table 4, with:
default via 1.1.1.1 dev eth1

I have rules:
32764:     from all to 1.1.1.10 lookup 4
32765:     from 1.1.1.10 lookup 4



If I ping from a natted host to 8.8.8.8, I am getting 
From 192.168.122.2 icmp_seq=1 Destination Net Unreachable

If I know add this rule
ip rule add from 192.168.122.0/24 to 8.8.8.8 lookup 4

The ping starts working. However I need to have this working for 
0.0.0.0/0 except 192.168.122.0/24. How should I implement something 
like:
ip rule add from 192.168.122.0/24 to !192.168.122.0/4 lookup 4

forwarding/routing traffic (+nat) to gw in a custom routing table

[Leroy Tennison]

You have some ambiguities which make it difficult to respond.

When you say "natted host", where is it coming from: 192.168.122.0/24 or the "1. network" (you didn't say what it's subnet mask was) or elsewhere?  Which interface is "connected" (directly or otherwise) to the Internet?

Am I understanding you correctly that the main routing table on this system has no default route?  Although not much is sacred, I normally set up a system with a default route in the main configuration and use alternate routing tables plus rules to deal with the exceptions.

Explain a little better what you're trying to accomplish in non-configuration terms, I'm confused by your configuration specifications.  I also tried your negation approach for 'ip rule add ...' and got an error because bash decided that the negation meant that history substitution was requested.


From: lartc-owner@vger.kernel.org <lartc-owner@vger.kernel.org> on behalf of Marc Roos <M.Roos@f1-outsourcing.eu>

Sent: Friday, November 8, 2019 9:48 AM

To: lartc <lartc@vger.kernel.org>

Subject: [EXTERNAL] forwarding/routing traffic (+nat) to gw in a custom routing table

 




I have two interfaces:

eth0 192.168.122.2

eth1 1.1.1.10



I have a routing table 4, with:

default via 1.1.1.1 dev eth1



I have rules:

32764:     from all to 1.1.1.10 lookup 4

32765:     from 1.1.1.10 lookup 4







If I ping from a natted host to 8.8.8.8, I am getting 

From 192.168.122.2 icmp_seq=1 Destination Net Unreachable



If I know add this rule

ip rule add from 192.168.122.0/24 to 8.8.8.8 lookup 4



The ping starts working. However I need to have this working for 

0.0.0.0/0 except 192.168.122.0/24. How should I implement something 

like:

ip rule add from 192.168.122.0/24 to !192.168.122.0/4 lookup 4


























Leroy Tennison
Network Information/Cyber Security Specialist
E: leroy@datavoiceint.com
2220 Bush Dr
McKinney, Texas
75070
www.datavoiceint.com
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