# Issue with HAProxy and Exchange 2016 with certificate based authentication

**URL:** <https://discourse.haproxy.org/t/issue-with-haproxy-and-exchange-2016-with-certificate-based-authentication/3480>\
**Category:** Help!\
**Created:** [February 6, 2019, 11:49am UTC](https://discourse.haproxy.org/t/issue-with-haproxy-and-exchange-2016-with-certificate-based-authentication/3480 "2019-02-06T11:49:35Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Kir](https://avatars.discourse-cdn.com/v4/letter/k/ea666f/32.png) [@Kir](https://discourse.haproxy.org/u/Kir)\
**Post date:** [February 6, 2019, 11:49am UTC](https://discourse.haproxy.org/t/issue-with-haproxy-and-exchange-2016-with-certificate-based-authentication/3480/1 "2019-02-06T11:49:35Z")

</div>

I have an Exchange 2016 as a backend that requires client certificates for accessing OWA and HAProxy as a reverse proxy. When I try to open OWA from Exchange directly everything is fine: I get a certificate prompt and can choose one that I want. But when I do the same through HAProxy I only get certificate prompt for HAProxy and then browser redirects me to Exchange authentication page without prompting certificate. The part of my config is below.

```
frontend fe_exch_443
    bind x.x.x.x:443 ssl crt /etc/ssl/certs/cert.pem ca-file /etc/ssl/certs/cert.crt verify optional crt-ignore-err all
acl ssl_connection ssl_fc
    acl path_owa path_beg -i /owa/
    http-request deny if path_check
    http-request redirect scheme https code 301 if !{ ssl_fc }
    use_backend bk_exchange_https_owa if path_owa
    default_backend be_exch_443
backend bk_exchange_https_owa
    option httpchk GET /owa/HealthCheck.htm
    http-check expect string 200\ OK
    server exch x.x.x.x:443 check ssl verify none maxconn 1000 weight 10 check

```

Any ideas? Thank you!