I want to use HAProxy to terminate TLS-encrypted TCP connnections and to pass the unencrypted TCP traffic to various backends based on the Server Name Indication used to initiate the TLS connection.
I have 3 services running on a backend server, each on a different port (5001, 5002, 5003). HAProxy binds to port 5000. I’d like to route connections to the first 2 servies by name or to the third if there is not a match. I am initiating the connecton to HAProxy using openssl s_client
. However, in the logs I can see that the connections are only ever routed to the default server, i.e. the SNI seems to be ignored.
DNS:
A record demo.sni.example.com 1.2.3.4
CNAME 1.sni.example.com pointing to demo.sni.example.com
CNAME 2.sni.example.com pointing to demo.sni.example.com
i.e. I’d like the following routing to occur:
SNI = 1.sni.example.com:5000 -> 1.2.3.4:5001
SNI = 2.sni.example.com:5000 -> 1.2.3.4:5002
anything else on port 5000 -> 1.2.3.4:5003
haproxy.cfg:
global
log stdout format raw local0 info
defaults
timeout client 30s
timeout server 30s
timeout connect 5s
option tcplog
frontend tcp-proxy
bind :5000 ssl crt combined-cert-key.pem
mode tcp
log global
tcp-request inspect-delay 5s
tcp-request content accept if { req_ssl_hello_type 1 }
use_backend bk_sni_1 if { req.ssl_sni -i 1.sni.example.com }
use_backend bk_sni_2 if { req.ssl_sni -i 2.sni.example.com }
default_backend bk_default
backend bk_sni_1
mode tcp
log global
balance roundrobin
server server1 1.2.3.4:5001 check
backend bk_sni_2
mode tcp
log global
balance roundrobin
server server1 1.2.3.4:5002 check
backend bk_default
mode tcp
log global
balance roundrobin
server server1 1.2.3.4:5003 check
combined-cert-key.pem
is a self-signed certificate file plus key where the CN is the IP of the server (1.2.3.4
) and there are SANs of all DNS values and the IP.
Connections initiated using openssl s_client
:
I have tried connecting via DNS (A & CNAME records, as well as IP):
echo test | openssl s_client -connect demo.sni.example.com:5000 -servername 1.sni.example.com
echo test | openssl s_client -connect 1.sni.example.com:5000 -servername 1.sni.example.com
echo test | openssl s_client -connect 1.2.3.4:5000 -servername 1.sni.example.com
However, all connections are routed to the default backend bk_default
.
What is causing HAProxy to not recognise the SNI servername? (I am using the latest HAProxy docker image: https://hub.docker.com/_/haproxy)