I'm suffering from sleep deprivation today so benzedrine.cx sounds inviting ;-)
Anyway a friend has a problem and I'd like a check on the sanity of my hazy proposed solution. All addresses are fictitious. X has a webserver which has address 1.2.3.4 He wants to change his hosting to another provider where a new server will be given address 5.6.7.8 The time of changeover is not entirely under X's control but the domain's DNS is. X would like all traffic to proceed to/from 1.2.3.4 until 5.6.7.8 is ready and then switch with absolutely minimal downtime. Of course.. My foggy brain says that it should be possible to use a box running pf to route requests arriving on one external interface (say 9.8.7.6) out another one (we have enough spare IPs on separate netblocks) to 1.2.3.4 until cut-over time and then pf.conf swaps to sending it to 5.6.7.8. If we put 9.8.7.6 into the DNS as the webserver address we should be able to transparently route the traffic to whichever real webserver we wish .......... I think. Then when all is stable we swap the DNS records to point to 5.6.7.8 and when no more traffic is seen to pass through our "black box router" we dispense with it. Will this scheme work? Do I need to use binat? (all addresses are global) does it matter if the webserver answers client requests and the traffic does not come back via the black box? Normally I'd throw some boxes together and try it but I need sleep before doing that and maybe someone cluey will tell me not to bother because it's crazy or (oh happy day) that of course it will work, don't i know pf is magic? Sure I do but i am not very magic just now and I'd like to give ny buddy a realistic guess as to how doable it is. Thanx, Rod (on list replies are fine but if you need to inform me privately of my insanity, please use the reply-to: address as the sender address is a spamtrap except to the list servers)
