Forwarding port 80 traffic to multiple Web servers behind the firewall

RDK

4/20/23, 6:54 AM

I want to set up two web servers behind my firewall, both accessible from Internet browser clients using the normal port 80 and the URL. For example server1 www.abc.com and server2 www.def.com.

I'm not an expert, but I think I understand how to use IPTABLEs to do a port forward. But what I don't know (or haven't found) is how to selectively do a forward based on the requested web server URL.

Assume the two servers are on the private IP addresses 10.0.0.100 and 10.0.0.110, respectively and my firewall router is on a public address 1.2.3.4. What I want is for port 80 traffic with URL www.abc.com to go to address 10.0.0.100 as port 80 and likewise for port 80 traffic with URL www.def.com to go to 10.0.0.110.

I suppose I could have the two servers listening on different ports if that is required, ie 9000 and 9100, instead of 80.

Can someone offer some ideas? Thanks

271

0 + 0

linux

iptables

forwarding

Score:5

Server

Tero Kilkanen

4/20/23, 7:18 AM

This cannot be done with IPTables. This is because the destination server is included in the HTTP request header field.

The first part of TCP connection is handshake, which sets up the connection between client and server. At this point, there is no information about the host name available. The HTTP request header field becomes after handshake.

Since IPTables simply forwards IP packets, it cannot forward the TCP handshake packets to correct destination.

You need to set up a reverse proxy, like HAProxy, nginx or Apache on the firewall machine.

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RDK

4/21/23, 6:07 AM

Thanks. I only mentioned IPTABLES since I had read about using it for port forwarding. Can you provide more details/references to using nginx and setting up a "reverse proxy" to achieve my goal?

RDK

4/26/23, 7:59 AM

Thanks again. With your hints I was able to find a wealth for references..

Elon Musk

I sit in a Tesla and translated this thread with Ai:

EN: Forwarding port 80 traffic to multiple Web servers behind the firewall

TH: การส่งต่อการรับส่งข้อมูลพอร์ต 80 ไปยังเว็บเซิร์ฟเวอร์หลายตัวที่อยู่หลังไฟร์วอลล์

RO: Redirecționarea traficului portului 80 către mai multe servere Web din spatele firewall-ului

RU: Перенаправление трафика порта 80 на несколько веб-серверов за брандмауэром

VI: Chuyển tiếp lưu lượng truy cập cổng 80 đến nhiều máy chủ Web phía sau tường lửa

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