linux Windows Server

Reverse proxy for Microsoft Exchange or RDS Gateway

When you have a bunch of applications all needing port 443 and a single public IP, you must use a reverse proxy.

For example, you have an Terminal services broker and an Exchange server which both need to use port 443.

You can set up an Haproxy instance that will proxy the request to the appropriate server. This is the configuration we use.
It uses SNI to find the requested hostname and direct you to the appropriate server.

######## Default values for all entries till next defaults section
option dontlognull # Do not log connections with no requests
option redispatch # Try another server in case of connection failure
option contstats # Enable continuous traffic statistics updates
retries 3 # Try to connect up to 3 times in case of failure
timeout connect 5s # 5 seconds max to connect or to stay in queue
timeout http-keep-alive 1s # 1 second max for the client to post next request
timeout http-request 15s # 15 seconds max for the client to send a request
timeout queue 30s # 30 seconds max queued on load balancer
timeout tarpit 1m # tarpit hold tim
backlog 10000 # Size of SYN backlog queue

balance roundrobin #alctl: load balancing algorithm
mode tcp #alctl: protocol analyser
option tcplog #alctl: log format
log global #alctl: log activation
timeout client 10800s #alctl: client inactivity timeout
timeout server 10800s #alctl: server inactivity timeout
default-server inter 3s rise 2 fall 3 #alctl: default check parameters

ssl-default-bind-options no-sslv3 no-tlsv10 no-tlsv11 no-tls-tickets
ssl-default-server-options no-sslv3
tune.ssl.default-dh-param 2048
log         stdout format raw  local0  info
# turn on stats unix socket
stats socket /var/run/haproxy.stat

listen stats
mode http
log global
bind :9000

maxconn 10

timeout queue 100s

stats enable
stats hide-version
stats refresh 30s
stats show-node
stats auth admin:password
stats uri /haproxy?stats

frontend https-in
bind :::443 v4v6 alpn h2,http/1.1 ssl crt /usr/local/etc/haproxy/certs/
log global
option httplog
mode http
http-response set-header Strict-Transport-Security max-age=31540000

use_backend if { ssl_fc_sni -i }
use_backend if { ssl_fc_sni -i }
use_backend if { ssl_fc_sni -i }
use_backend if { ssl_fc_sni -i }


mode http
server exchange exchange_server.local:443 ssl verify none maxconn 10000 check #alctl: server exchange configuration.

mode http
server rds rds_server.local:443 ssl verify none maxconn 10000 check #alctl: server rds configuration.

mode http
server website website_server.local:443 ssl verify none maxconn 10000 check #alctl: server rds configuration.

Docker linux Security

Traefik 2 and Nextcloud

I use Traefik and Nextcloud on docker and it took me a few tries to get it to the point where nextcloud would not complain about configuration issues.

Here is the configuration I ended up with:

- "traefik.enable=true"
- ""
- "traefik.http.routers.nextcloud.middlewares=nextcloud,nextcloud_redirect"
- "traefik.http.routers.nextcloud.rule=Host(``)"
- ""
- "traefik.http.routers.nextcloud.entrypoints=websecure"
- "traefik.http.routers.nextcloud.tls.certresolver=mydnschallenge"
- "traefik.http.middlewares.nextcloud.headers.customFrameOptionsValue=ALLOW-FROM"
- "traefik.http.middlewares.nextcloud.headers.contentSecurityPolicy=frame-ancestors 'self' *"
- "traefik.http.middlewares.nextcloud.headers.stsSeconds=155520011"
- "traefik.http.middlewares.nextcloud.headers.stsIncludeSubdomains=true"
- "traefik.http.middlewares.nextcloud.headers.stsPreload=true"
- "traefik.http.middlewares.nextcloud.headers.referrerPolicy=same-origin"
- "traefik.http.middlewares.nextcloud.headers.customFrameOptionsValue=SAMEORIGIN"
- "traefik.http.middlewares.nextcloud_redirect.redirectregex.regex=/.well-known/(card|cal)dav"
- "traefik.http.middlewares.nextcloud_redirect.redirectregex.replacement=/remote.php/dav/"

This answers a question that’s been asked a few times on this post, which is “how to configure HSTS on Traefik 2”


Proftpd on CIFS share

For several of our clients, we provide an FTP server on a linux server, with the files hosted on a windows 2008r2 server and authentication being handled by active directory through proftpd-ldpap.

The windows share are automatically mounted on access with autofs in a /srv/ftp subfolder, and users are jailed in yet another level of subdirectory using proftpd.

I hit a bit of a wall recently with this setup, as everything seemed to be in order, autofs mounted the directory, proftpd allowed login with ldap auth, but for some reason I couldn’t write anything.

If I pointed proftpd at a local directory however, write was fine.


I finally found out that proftpd was trying to use “chmod” on every write, and with SMB < 3, it failed, resulting in a “permission denied” error and nothing whatsoever in the logs.


I fixed it by mounting the CIFS share with the “noperm” option:

homes -fstype=cifs,rw,credentials=/etc/cifscredentials,gid=nogroup,uid=proftpd,vers=2.1,noperm ://SERVER/SHARE\$/SFTP