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I want it to balance traffic for the network, but one computer needs to walk on the Inernet from one ip (now it appears sometimes as ip1 and sometimes as ip2). Still it needs to switch to another channel, if default is broken. How can I achieve this?

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up vote 1 down vote accepted

If you want the same IP even when failing over to another ISP you have to use BGP and get IP space assigned to you (ARIN in north America, RIPE for Europe, APNIC asia-pac...), this is not cheap.

Then there's ~10k worth of routers, and fixed ethernet/fibre links (as very few carriers will do BGP over *DSL, and none over cable)

Most of the simple "fail-over" routers can be set to a fail-over mode instead of load-balancing, the better ones even have rules so some sorts of traffic always prefer one interface over another.

Your router can be set to this mode, see section 5.6.1 of the manual:

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I know about fail-over mode and it suites me good except the backup line is never used. So I prefer load-balancing. But it breaks sessions! For example, I enter forum from one ip and then it changes. I have "access denied". Maybe, I don't understand how to use load balancing mode properly? – lexsys Jun 10 '09 at 11:41
As I suggested some better routers would allow you to have all HTTP over one connection and everything else over the other, spreading the load a bit. Another option might be some form of "sticky" load balancing to always have the same PCs using the same connection, that only works if the connection is shared. Otherwise yell at the people breaking you because your IP changes, they shouldn't do that these days as many mobile networks don't give a reliable IP address, and there's many other reasons. – LapTop006 Jun 10 '09 at 12:27

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