If I had an IP address (for example bought range for my company), and 2 ISPs fibres, how would it be possible to set my network card to have same IP adress accessible from both connections? (know its possible, but what are requirements)

I plan on running few servers for my company, and would like them to be accessible from s1.example.com and s2.example.com.

I would want to have 2 connections, if one is down other works. So, how does IP assignment work and is that possible with any ISP?

PS: Did not find any question/answer for my question, will remove if its duplicate

  • 2
    That won't work for single IP addresses. You'll need to own at least a /24 IPv4 subnet to advertise that route over BGP.
    – Zac67
    Jun 3, 2019 at 20:36
  • @Zac67 So if I own /24 I can route it anywhere I want?
    – Grzegorz
    Jun 3, 2019 at 20:47
  • 1
    If your ISPs let you advertise you can.
    – Zac67
    Jun 3, 2019 at 21:04
  • @Zac67 could you point me to any source of knowledge how it works?
    – Grzegorz
    Jun 3, 2019 at 21:41
  • The big problem is that the RIRs no longer have any IPv4 addresses to assign. You will need to go out on the open market to see if you can purchase a block, then you will still need to jump through the RIR hoops to get it assigned to you.
    – Ron Maupin
    Jun 4, 2019 at 13:18

1 Answer 1


First, you need to apply for an autonomous system number (AS) and your own /24 network at your RIR. You also need to make sure that your ISPs support peering via BGP.

Then, you advertise your network under your AS using BGP on your WAN connections as multi-homed. Your ISPs accept that advertisement and in turn advertise the AS route on their peering interfaces, so the route propagates through the Internet.

  • 3
    Don't forget to include one (or possibly more) routers capable of doing BGP.
    – Teun Vink
    Jun 4, 2019 at 5:31

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