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Dual uplinks means dual public IPs

Posted: Mon Jul 16, 2018 5:56 pm
by azurtem
Hi
I have clients that use dual uplinks for their customer sites
The second uplink, generally via LTE, serves as a backup access
The problem is that both uplinks obviously have their own public IP addresses
Therefore when in backup mode the site has to be reached via a different IP address
What alternative solutions/options exist that would allow us to present a single address to the outside world whether we are in normal or backup mode ?

thanks
yann

Re: Dual uplinks means dual public IPs

Posted: Mon Jul 16, 2018 7:38 pm
by Cha0s
Set up a MikroTik (CHR or x86) on a datacenter somewhere, then create tunnels from the location to the datacenter.
1 tunnel per uplink.

Then route all the traffic via the tunnels and eventually via the gateway of the datacenter router. If uplink1 is down, then the traffic can failover via uplink2.
This way your source IP to the outside world will be the IP of the datacenter MikroTik.

Since regardless of the uplink you reach the internet with the same IP, nothing breaks. NAT keeps working, connections do not drop and you can make it pretty much seamless, with failover times at ~1second using BGP/BFD.

I use this method for almost a decade and during failover not a single connection fails. (VoIP is another story of course).

Re: Dual uplinks means dual public IPs

Posted: Mon Jul 16, 2018 7:55 pm
by azurtem
Nice one Chaos; thank you

Re: Dual uplinks means dual public IPs

Posted: Mon Jul 16, 2018 8:06 pm
by gerakon
/ip cloud or some other DDNS service if you don't happen to have a datacenter laying around.
Granted ip cloud has had a bit of flakiness from time to time it usually works for me for remote administration at least. There is supposed to be a new /ip cloud service from Mikrotik sometime soon to address some of the flakiness problems. If you are trying to host a website or something that needs a more reliable/always working connection, this probably isn't the right answer.