CODEWITHSUNDEEP
tcpserverport
vidstige
vidstige

Reputation: 13079

What hostname did the client use to connect to my TCP server?

In http the client supplies the hostname it used to connect to the service with. Now, for bare TCP connections, is there something similar one can do? My scenario is I have a service that has multiple open TCP ports and that works fine, but for convenience I would like to use the same port and subdomains. Is there any layer I can add on top (like a load balancer), or change the service? I have control over most things, basically anything goes.

Example: Today I can connect to two TCP services like so: foobar.com:1001 and foobar.com:1002. Is it possible to have e.g. service-1.foobar.com:1000 go to foobar.com:1001 and service-2.foobar.com:1000 go to foobar.com:1002.

Upvotes: 0

Views: 1513

Answers (2)

David V
David V

Reputation: 13

If I understand your question correctly based on your example then no it is not possible. In this case, there is no difference between an HTTP and TCP connection.

In both cases, the hostname is simply resolved to an ip address. If you setup DNS resolution for foobar.com, service-1.foobar.com, service-2.foobar.com to point to the same ip address then they will all go to the same machine.

I have at times needed to have a service running on a different port internally than it is accessible externally. For that, if you are running on Linux, you can simply use iptables to do the port forwarding.

You can find other stack overflow questions/answers for setting up the port forwarding.

https://serverfault.com/questions/140622/how-can-i-port-forward-with-iptables

Upvotes: 0

Prabhu
Prabhu

Reputation: 3541

Different services can bind to same port but on different IP. Hence different domains shall resolve to different IPs : Port combination [where Port is same for all services]. And you can use Proxy service as from HA Proxy to route connections to final destination.

Upvotes: 1

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