1

I am trying to extend a custom haproxy log-format by adding [req.ssl_sni]. The haproxy version used is 1.6.3 on Ubuntu.

The frontend is configured in the following way:

bind *:443
mode tcp

tcp-request inspect-delay 5s
tcp-request content accept if { req_ssl_hello_type 1 }
tcp-request content reject

log-format [...]{%[req.ssl_sni]}

Where [...] denotes other log options which are working fine. The frontend is running in TCP mode, forwarding TLS sessions without decrypting them.

The expected log output would be something similar to {my.server.com} for valid TLS sessions. The log output I am seeing is always {-} (a dash instead of the server name), even when the TLS session is successfully handled by the backend server. What do I have to change to see the actual SNI value in the logs?

2

Using capture before accept solved it for me.

frontend https-in
  mode tcp
  tcp-request inspect-delay 3s
  tcp-request content capture req.ssl_sni len 10
  log-format "capture0: %[capture.req.hdr(0)]"
  tcp-request content accept if { req_ssl_hello_type 1 }
  use_backend test_0 if req.ssl_sni -m end /test

Found solution in here: https://discourse.haproxy.org/t/log-sni-in-tcp-mode/1534/2

0

Maybe the problem was in the name used? I see "req.ssl_sni" in the question and "req_ssl_sni" in examples for SNI.

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