WAN connectivity ( ISP1 & ISP2)

[Umesh]

Hi Greetings to you all,

I need your comment for the below screenshot-

First I will explain that I have taken two ISP for internet connectivity in the organization -

both ISP have provided below IP pool-

Airtel - 1.1.1.0/30

           - 3.3.3.0/29

Voda - 2.2.2.0/30

          - 4.4.4.0/29

so which IP should I use for connecting both internet lines, as far as I think /30 for both internet lines and /29 used for servers. Is it correct what I am saying.

I have servers - Web server, Email server, DNS server, NTP server, etc.

Note - My question is why should we use separate  IPs for servers.

please explain if you understand from the below screenshot which I have prepared as per my understanding.

[jintrah_FTNT]

Hi Umesh,

Yes, your understanding on using /30 subnet for internet links and /29 for hosting servers is correct.

I believe you intend to use an IP address from each ISP pool to host a server for redundancy purpose, and that you do own a BGP AS number to host them on a single IP address to achieve redundancy when either of the internet links fail.

best regards,

Jin

[Umesh]

Hi Jin,

I have one webserver just I want to know what would be configuration roadmap on the firewall with one public IP can you make me clarify it.

thank you

[jintrah_FTNT]

Hi Umesh,

Please see the article Technical Tip: Configuring Hairpin NAT (VIP) - Fortinet Community which would be helpful.

Best regards,

Jin

[akristof]

Hi,

Thank you for your question. You can use 1 real IP server and you create 2 VIPs, each for one public IP from one pool and you can DNAT traffic. Usually, each provider will give you different pools because they have different super nets assigned by IANA. And unless you have dynamic routing between both ISPs, ISP1 will advertise network 3.3.3.0/29 to internet while ISP2 will advertise 4.4.4.0/29 to internet.