[CentOS] Routing issue

Wed Oct 10 11:32:10 UTC 2012
Steve Clark <sclark at netwolves.com>

On 10/09/2012 05:36 PM, Ljubomir Ljubojevic wrote:
> On 09/27/2012 05:24 PM, Gordon Messmer wrote:
>> On 09/27/2012 06:36 AM, Steve Clark wrote:
>>> I was trying to figure out what criteria to use to mark the connection.
>>> FTP is such a
>>> braindead application, using to channels and active and passive mode.
>>> What really
>>> needs to happen is someway to tell the kernel to recheck the routing
>>> after SNAT.
>> I'm mostly sure that if you mark the *connection* to the FTP server, the
>> related data will follow its path.
>> Again, multipath routing is complex, and Shorewall will do it properly.
>>     At the very least, I recommend building a working configuration with
>> Shorewall and then reading the rules that it compiles to understand why
>> it handles routing the way that it does.
> Steve, what you need is to send packages of particular stream via
> particular ISP in situation where stupid load balancing will brake a
> connection, send it via different ISP and thus change the clients IP.
> Shorewall and it's Multi-ISP config is only thing you need for this to work.
Hi Ljubomir,

Thanks for the response. We have 450 units in the field and have only needed to do this at one site. I am
using a userspace script to monitor the viability of each isp and changing the routing accordingly as
described in the LARTC document. Our units in the field use CentOS so we don't want to use a
custom kernel outside of what CentOS provides. That's why I am reluctant to use the patches at



Stephen Clark
Director of Technology
Phone: 813-579-3200
Fax: 813-882-0209
Email: steve.clark at netwolves.com