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Date: Tue, 24 Jan 2017 12:25:33 -0800 (PST)
From: Don Lewis <truckman@FreeBSD.org>
Subject: Re: inheriting fib from an interface
To: eugen@grosbein.net
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In-Reply-To: <20170124095539.GA18648@rdtc.ru>
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On 24 Jan, Eugene Grosbein wrote:
> On Mon, Jan 23, 2017 at 05:31:22PM -0800, Don Lewis wrote:
> 
>> Let's say that I have an application running on a server that is
>> connected to the Internet via two different ISPs and is using IP
>> addresses (ISP A:10.0.0.10 and ISP B:192.168.1.10) delegated by those
>> two ISPs on it's two interfaces.  Responses to requests sent to
>> 10.0.0.10 should be sent via ISP A, and responses to requests sent to
>> 192.168.1.10 should be ISB B.
>> 
>> There are a couple of different ways that I can think of to do this:
>> 
>> 1) Put the server behind another FreeBSD box that uses policy-based
>>  routing to forward the outbound packets to the desired ISP.  My
>>  understanding is that this only works for packet forwarding and not
>>  for locally generated packets.
> 
> Single command "ipfw add 2000 fwd $ispgw2 ip from $ip2 to any out xmit $isp1_iface"
> works for locally generated packets too.
> 
> It "fixes" outgoing routing path for packets
> from IP belonging to "non-default" ISP2 when default route points to ISP1.

Thanks, that looks very promising!