# SSL Handshake issue

**URL:** <https://discourse.haproxy.org/t/ssl-handshake-issue/2524>\
**Category:** Help!\
**Created:** [May 22, 2018, 8:40am UTC](https://discourse.haproxy.org/t/ssl-handshake-issue/2524 "2018-05-22T08:40:36Z")\
**Posts on this page:** 10\
**Page:** 1

<div class="post-metadata">

**Author:** ![ruzzetto](https://avatars.discourse-cdn.com/v4/letter/r/d9b06d/32.png) [@ruzzetto](https://discourse.haproxy.org/u/ruzzetto)\
**Post date:** [May 22, 2018, 8:40am UTC](https://discourse.haproxy.org/t/ssl-handshake-issue/2524/1 "2018-05-22T08:40:36Z")

</div>

Hi all,  
I have a strange issue with haproxy after performed some package upgrades on my RHEL machine. Everything was fine but now when I try to get a resource (the second backend) i got 503 Service Unavailale.

I found error messages:

1. haproxy[9190]: backend jboss-fe-bus has no server available!
2. Server jboss-fe-bus/nodo1 is DOWN, reason: Layer6 invalid response, info: “SSL handshake failure”, check duration: 27ms. 0 active and 0 backup servers left. 0 sessions active, 0 requeued, 0 remaining in queue.

Here’s my haproxy.cfg:

_frontend myapp \*:80_  
_bind \*:80_  
_bind \*:443 ssl crt /etc/pki/tls/private/mycertificate.pem_  
_redirect scheme https if !{ ssl\_fc }_  
_option forwardfor_  
_acl host\_myapp1\_bus hdr(host) -i app.mydomain.it_  
_acl is\_root path -i /_  
_acl is\_myapp1\_bus path\_beg /MYAPP_  
_acl is\_myapp3 path\_beg /main-web_  
_redirect code 302 location /MYAPP/ if is\_root host\_myapp1\_bus_  
_use\_backend iis if host\_myapp1\_bus is\_myapp1\_bus_  
_use\_backend jboss-fe-bus if host\_myapp1\_bus is\_myapp3_

_backend iis_  
_balance roundrobin_  
_cookie SERVERID insert indirect nocache_  
_server nodo1 server01.domain.lan:443 weight 1 maxconn 100 check ssl verify none check cookie s1_

_backend jboss-fe-bus_  
_balance roundrobin_  
_server nodo1 server02.domain.lan:9443 weight 1 maxconn 100 check ssl verify none_

The server “server02.domain.lan” is the same as haproxy.

Maybe new packages change something?  
Thanks a lot,  
Fabio

---

<div class="post-metadata">

**Author:** ![lukastribus](https://avatars.discourse-cdn.com/v4/letter/l/7ea924/32.png) [@lukastribus](https://discourse.haproxy.org/u/lukastribus)\
**Post date:** [May 22, 2018, 10:27am UTC](https://discourse.haproxy.org/t/ssl-handshake-issue/2524/2 "2018-05-22T10:27:56Z")

</div>

I assume we are talking about the openssl package that has been updated.  
Can you tell what exact openssl package release you are running now, and what worked previously?  
I assume the connection to the server01.domain.lan servers works fine?

Also please share the ouput of `haproxy -vv`.

Does the connection to server02 work when you remove the `check` keyword from the server line (so it is a health check problem)?

---

<div class="post-metadata">

**Author:** ![ruzzetto](https://avatars.discourse-cdn.com/v4/letter/r/d9b06d/32.png) [@ruzzetto](https://discourse.haproxy.org/u/ruzzetto)\
**Post date:** [May 22, 2018, 10:49am UTC](https://discourse.haproxy.org/t/ssl-handshake-issue/2524/3 "2018-05-22T10:49:54Z")

</div>

Hi,  
thanks for your answer.

Please follow details:

haproxy -vv output:

HA-Proxy version 1.5.18 2016/05/10  
Copyright 2000-2016 Willy Tarreau [willy@haproxy.org](mailto:willy@haproxy.org)

Build options :  
TARGET = linux2628  
CPU = generic  
CC = gcc  
CFLAGS = -O2 -g -fno-strict-aliasing -DTCP\_USER\_TIMEOUT=18  
OPTIONS = USE\_LINUX\_TPROXY=1 USE\_ZLIB=1 USE\_REGPARM=1 USE\_OPENSSL=1 USE\_PCRE=1

Default settings :  
maxconn = 2000, bufsize = 16384, maxrewrite = 8192, maxpollevents = 200

Encrypted password support via crypt(3): yes  
Built with zlib version : 1.2.7  
Compression algorithms supported : identity, deflate, gzip  
Built with OpenSSL version : OpenSSL 1.0.2k-fips 26 Jan 2017  
Running on OpenSSL version : OpenSSL 1.0.2k-fips 26 Jan 2017  
OpenSSL library supports TLS extensions : yes  
OpenSSL library supports SNI : yes  
OpenSSL library supports prefer-server-ciphers : yes  
Built with PCRE version : 8.32 2012-11-30  
PCRE library supports JIT : no (USE\_PCRE\_JIT not set)  
Built with transparent proxy support using: IP\_TRANSPARENT IPV6\_TRANSPARENT IP\_FREEBIND

Available polling systems :  
epoll : pref=300, test result OK  
poll : pref=200, test result OK  
select : pref=150, test result OK  
Total: 3 (3 usable), will use epoll.  
###############################

openssl installed (from yum history) version:

Updated openssl-1:1.0.1e-60.el7\_3.1.x86\_64 @rhel-7-x86\_64-latest  
Update 1:1.0.2k-12.el7.x86\_64 @rhel-7-server-rpms  
Updated openssl-libs-1:1.0.1e-60.el7\_3.1.x86\_64 @rhel-7-x86\_64-  
################################

So the connection to server01 is fine and if i try to connect directly to [https://server02:9443](https://server02:9443) it also works. I tried to remove check keyword and I got 502 Bad Gateway error.

Thanks,  
Fabio

---

<div class="post-metadata">

**Author:** ![lukastribus](https://avatars.discourse-cdn.com/v4/letter/l/7ea924/32.png) [@lukastribus](https://discourse.haproxy.org/u/lukastribus)\
**Post date:** [May 22, 2018, 2:19pm UTC](https://discourse.haproxy.org/t/ssl-handshake-issue/2524/4 "2018-05-22T14:19:26Z")

</div>

What does:

```
openssl version
openssl s_client -connect server02:9443

```

from your haproxy box report (exactly)?

---

<div class="post-metadata">

**Author:** ![ruzzetto](https://avatars.discourse-cdn.com/v4/letter/r/d9b06d/32.png) [@ruzzetto](https://discourse.haproxy.org/u/ruzzetto)\
**Post date:** [May 22, 2018, 3:01pm UTC](https://discourse.haproxy.org/t/ssl-handshake-issue/2524/5 "2018-05-22T15:01:46Z")

</div>

HI,  
my colleague is working with me looking for a fix. He downgraded openssl package to previous release with no effects.

Anyway here’s the output of commands:

openssl version

> OpenSSL 1.0.2k-fips 26 Jan 2017

openssl s\_client -connect server02:9443

> CONNECTED(00000003)  
> depth=1 DC = XX, DC = XXX, CN = XXXX-CA  
> verify return:1  
> depth=0 C = X, ST = XX, L = XX, O = X X, OU = X, CN = server02  
> verify return:1  
> 140477279786896:error:14082174:SSL routines:ssl3\_check\_cert\_and\_algorithm:dh key too small:s3\_clnt.c:3636:  
> Certificate chain  
> 0 s:/C=XX/ST=X/L=X/O=XX /OU=ICT/CN=server02.  
> i:/DC=XX/DC=XX/CN=XX-XX-CA  
> 1 s:/DC=XX/DC=XX/CN=XX-XX-CA  
> i:/DC=XX/DC=XX/CN=XX-XX-CA  
> Server certificate  
> -----BEGIN CERTIFICATE-----
> 
> – OMISSIS –
> 
> -----END CERTIFICATE-----  
> subject=/C=X/ST=XX/L=XX/O=XX/OU=X/CN=server02  
> issuer=/DC=XX/DC=XX/CN=XX-XX-CA  
> No client certificate CA names sent  
> Server Temp Key: DH, 768 bits  
> SSL handshake has read 2996 bytes and written 7 bytes  
> New, (NONE), Cipher is (NONE)  
> Server public key is 2048 bit  
> Secure Renegotiation IS supported  
> Compression: NONE  
> Expansion: NONE  
> No ALPN negotiated  
> SSL-Session:  
> Protocol : TLSv1  
> Cipher : 0000  
> Session-ID: 5B042E19AF89DE3105EA358130EC78CF188DF3CC15147275DA8110F3FE90E938  
> Session-ID-ctx:  
> Master-Key:  
> Key-Arg : None  
> Krb5 Principal: None  
> PSK identity: None  
> PSK identity hint: None  
> Start Time: 1527000600  
> Timeout : 300 (sec)  
> Verify return code: 0 (ok)

I replace sensitive information with “XX”.  
Thanks,  
Fabio

---

<div class="post-metadata">

**Author:** ![lukastribus](https://avatars.discourse-cdn.com/v4/letter/l/7ea924/32.png) [@lukastribus](https://discourse.haproxy.org/u/lukastribus)\
**Post date:** [May 22, 2018, 5:19pm UTC](https://discourse.haproxy.org/t/ssl-handshake-issue/2524/6 "2018-05-22T17:19:11Z")

</div>

Check this out:

```
140477279786896:error:14082174:SSL routines:ssl3_check_cert_and_algorithm:dh key too small:s3_clnt.c:3636:

```

and:

```
Server Temp Key: DH, 768 bits

```

You configured a tiny DH group in SSL backend server, that is causing the issue here as openssl refuses to connect to such a insecure configuration. Configure DH correctly or remove DH from the backend.

If you need a fast workaround from haproxy, try adding the following to your server line (`server nodo1 server02.domain.lan:9443 ...`), which disables DHE ciphers so you’d avoid hitting DH groups in the first place:

```
ciphers ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA256:ECDHE-ECDSA-AES128-SHA:ECDHE-RSA-AES256-SHA384:ECDHE-RSA-AES128-SHA:ECDHE-ECDSA-AES256-SHA384:ECDHE-ECDSA-AES256-SHA:ECDHE-RSA-AES256-SHA:ECDHE-ECDSA-DES-CBC3-SHA:ECDHE-RSA-DES-CBC3-SHA:EDH-RSA-DES-CBC3-SHA:AES128-GCM-SHA256:AES256-GCM-SHA384:AES128-SHA256:AES256-SHA256:AES128-SHA:AES256-SHA:DES-CBC3-SHA:!DSS
```

---

<div class="post-metadata">

**Author:** ![ruzzetto](https://avatars.discourse-cdn.com/v4/letter/r/d9b06d/32.png) [@ruzzetto](https://discourse.haproxy.org/u/ruzzetto)\
**Post date:** [May 23, 2018, 7:40am UTC](https://discourse.haproxy.org/t/ssl-handshake-issue/2524/7 "2018-05-23T07:40:14Z")

</div>

Thanks @lukastribus, I tried your workaround but it doesn’t work.  
How can I modify DH group in SSL backend in order to fix it?

Fabio

---

<div class="post-metadata">

**Author:** ![lukastribus](https://avatars.discourse-cdn.com/v4/letter/l/7ea924/32.png) [@lukastribus](https://discourse.haproxy.org/u/lukastribus)\
**Post date:** [May 23, 2018, 9:10am UTC](https://discourse.haproxy.org/t/ssl-handshake-issue/2524/8 "2018-05-23T09:10:49Z")

</div>

What’s your backend software? Does your certificate contain specific DH parameters?

Why do you need HTTPS anyway between haproxy and this backend server? You said it is on the same server as haproxy?

---

<div class="post-metadata">

**Author:** ![ruzzetto](https://avatars.discourse-cdn.com/v4/letter/r/d9b06d/32.png) [@ruzzetto](https://discourse.haproxy.org/u/ruzzetto)\
**Post date:** [May 23, 2018, 9:23am UTC](https://discourse.haproxy.org/t/ssl-handshake-issue/2524/9 "2018-05-23T09:23:44Z")

</div>

@lukastribus backend software is a JBoss server and there would need too much modify to switch to http.

---

<div class="post-metadata">

**Author:** ![lukastribus](https://avatars.discourse-cdn.com/v4/letter/l/7ea924/32.png) [@lukastribus](https://discourse.haproxy.org/u/lukastribus)\
**Post date:** [May 23, 2018, 8:58pm UTC](https://discourse.haproxy.org/t/ssl-handshake-issue/2524/10 "2018-05-23T20:58:29Z")

</div>

This may help you:

> **[How To Fix "Server has a weak ephemeral Dillie-Heffman public key" For Jboss...](https://www.reinisfischer.com/how-fix-server-has-weak-ephemeral-dillie-heffman-public-key-jboss-server)**
>
> A few days ago a customer of mine experienced an error by not being able to access his management system on intranet I built a few years ago. The error we got was following: "Server has a weak ephemeral Dillie-Heffman public key" or...