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Re: Establish TCP connection to upstream when client connection made to listener

Phillip Odam
March 21, 2020 10:58AM
Hi Francis

Thanks for the detail. And you're quite right the issue had nothing to
do with NGINX, it was the loadbalancer out in front of NGINX.

Cheers

Phillip

On 3/20/20 10:43 AM, Francis Daly wrote:
> On Fri, Mar 20, 2020 at 09:57:40AM -0400, Phillip Odam wrote:
>
> Hi there,
>
>> I'm looking for when a client establishes a TCP connection to an IP and
>> port, that NGINX is listening on, that NGINX, without waiting on data being
>> transmitted from the client to NGINX, would establish a TCP connection to
>> the upstream.
> What happened when you tried it?
>
> A quick test here of "nc -l 9005", plus nginx.conf with
>
> ==
> stream {
> server {
> listen 9001;
> proxy_pass 127.0.0.3:9005;
> }
> }
> ==
>
> and "tcpdump -nn -i any -X -s 0 port 9005 or port 9001", seems to show
> that "nc localhost 9001" leads to a tcp handshake involving port 9001
> (from the client to nginx) and a tcp handshake involving port 9005
> (from nginx to the upstream).
>
>> Trouble with this though, NGINX then can't fully support reverse proxying
>> protocols where the server provides a response upon TCP connection eg. SSH2,
>> MySQL. You're instead dependent on the client handling the lack of initial
>> server response and that after the client sends its first lot of data it'll
>> then receive the server's initial response.
> Do you have a specific test case that shows this problem?
>
> ==
> stream {
> server {
> listen 9001;
> proxy_pass 127.0.0.3:22;
> }
> }
> ==
>
> and "ssh -v -p 9001 localhost" would seem to indicate that it Just Works.
>
> Perhaps my testing is wrong?
>
> f
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Subject Author Posted

Establish TCP connection to upstream when client connection made to listener

Phillip Odam March 20, 2020 09:58AM

Re: Establish TCP connection to upstream when client connection made to listener

Francis Daly March 20, 2020 10:44AM

Re: Establish TCP connection to upstream when client connection made to listener

Phillip Odam March 21, 2020 10:58AM



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