having issues switching an ip address from my vps to a dedicated machine. feels like it still routes to the vps. does anyone know if I have to do anything esle than deassign/assign?
waited for 10 minutes before rolling back
are both on the same vlan? treat them both as if they are physical machines
i have a /29 and currently assign 3 ip's to my dedicated and 2 to my vps. when trying to switch the most "active" ip, it just doesn't seem to work
i tried a similar switch with an unused ip some days ago which worked
is there something i fundamentally fail to understand here? :/
sounds like you've done your homework, if the vps stops responding to it and the other system starts, arp cache timeouts should be all that is in your way
its possible you hit a lucky time in the arp cache timeout in your testing, no guarantees though
the old system doesn't respond to old ip (and ifconfig doesn't show it), new machine allocates it (shows up in ifconfig), but i cannot have 10 minutes more fo downtime not knowing :(
update dns to point to another ip responded to by the new system?
i don't control all domain names pointing to that ip
jbergstroem: Is the IP being assigned to a NIC that already has an IP and therefore assigning multiple IPs to the sam MAC address or is this a new MAC ?
_mnathani_: i bond the two interfaces to one mac address that has multiple ip addresses assigned to it
i use the ip that is moved as primary (all outgoing is going through it)
can you try making the IP you are moving the primary IP on the dedicated and ping the gateway
that would update the ARP I am pretty sure
i did
gateway didn't respond
thats odd
yes, i agree
could you ping an outside internet ip?
like say 8.8.8.8
no, nothing from the machine since outgoing traffic was meant to go through that ip
things i bind to the other ip's work fine though
Did your VPS get upgraded to use gigabit networking?
no
'beta' and was moving any time anyway
and the gateway assigned is the same on both the VPS and dedicated?
yes, same netmasks, broadcasts etc
when you move the IP from the VPS, do you assign another IP / Primary to the VPS ?
yes, i have two assigned so i don't have to mess with kvm.
the second ip i used to experiment this transition with a coulpe of days ago. worked well.
can you ping the troublesome ip from the vps after the move to dedicated?
no. not from anywhere
my understanding of ARP networks infrastructure is that they place VPS and Dedicated on the same VLAN, so in thery it should work just fine
yes, that's what help says as well, and from moving other ip's im inclined to agree
are you able to flush arp cache and retry?
how?
what OS?
linux
but is it really my arp cache that needs to be flushed?
it might be whats causing the gateway to retain the VPS MAC address for the troubled IP
http://www.lainoox.com/display-add-flush-arpcache-linux-arp/
instead of flush, you could delete the specific entry
arp cache displays same records
like:
arp -i eth0 -d 10.11.12.13
on dedicated or virtual?
yeah, i know how to clear it, but are not very willing to get additional downtime to try it
on both
after removing from vps it should no longer show the old mac, it should update to the new mac from dedicated
but shouldn't the cached gateway mac be the same on both machines?
yes, gateway mac should be the same
i don't think arp caches locally assigned ip addresses.
right
I was going for the troubled IP after assigning to dedicated, then ping from vps and check cache
just tried, and nope.
no cache.
when pinging the ip from outside the network, does it timeout when moving to dedicated?
or does the old vpn still respond?
*vps
i can't reach the gateway at all if i migrate the ip address
times out
old vpn does not have that ipa ddress assigned, so it doesn't respond
there. just switched
seems like some kind of security on the switch port
one other thing, your dedicated server has 2 network interfaces, are you doing any kind of redundant load balancing configuration?
took 3 minutes though
so its working now?
yes
so, nothing from my end