The service has started.
Nagios is installed on a member server (not DC). A proxy server with HAproxy is set up for remote access.
If the server is accessed directly in the local network, it is shown that the daemon is running and all services can be accessed and displayed.
If access is remote, the request is forwarded to the same member server via a HAproxy. Then the Nagios message (Nagios Core) "Not running" appears.
A trace showed that with local access
and with remote accessip.of.nagios.server - Administrator [13/Feb/2020:20:24:28 +0100] "GET /nagios3/side.php HTTP/1.1" 200 1438 "https://local.com/nagios3/" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10.13; rv:72.0) Gecko/20100101 Firefox/72.0"
ip.of.nagios.server - Administrator [13/Feb/2020:20:24:28 +0100] "GET /nagios3/main.php HTTP/1.1" 200 2885 "https://local.com/nagios3/" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10.13; rv:72.0) Gecko/20100101 Firefox/72.0"
ip.of.nagios.server - Administrator [13/Feb/2020:20:24:28 +0100] "GET /nagios3/stylesheets/common.css?4.3.4 HTTP/1.1" 200 2905 "https://local.com/nagios3/side.php" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10.13; rv:72.0) Gecko/20100101 Firefox/72.0"
ip.of.nagios.server - Administrator [13/Feb/2020:20:24:29 +0100] "GET /nagios3/stylesheets/nag_funcs.css?4.3.4 HTTP/1.1" 200 986 "https://local.com/nagios3/main.php" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10.13; rv:72.0) Gecko/20100101 Firefox/72.0"
ip.of.nagios.server - Administrator [13/Feb/2020:20:24:29 +0100] "GET /cgi-bin/nagios/statusjson.cgi?query=programstatus HTTP/1.1" 200 1565 "https://local.com/nagios3/main.php" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10.13; rv:72.0) Gecko/20100101 Firefox/72.0"
There is a difference in the last "GET" of the path but I have no explanation for it.ip.of.haproxy.server - Administrator [13/Feb/2020:20:23:55 +0100] "GET /nagios/ HTTP/1.1" 200 4403 "-" "Mozilla/5.0 (iPhone; CPU iPhone OS 13_3 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/13.0.4 Mobile/15E148 Safari/604.1"
ip.of.haproxy.server - Administrator [13/Feb/2020:20:23:56 +0100] "GET /nagios/main.php HTTP/1.1" 200 2833 "https://remote.com/nagios/" "Mozilla/5.0 (iPhone; CPU iPhone OS 13_3 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/13.0.4 Mobile/15E148 Safari/604.1"
ip.of.haproxy.server - Administrator [13/Feb/2020:20:23:56 +0100] "GET /nagios/side.php HTTP/1.1" 200 1539 "https://remote.com/nagios/" "Mozilla/5.0 (iPhone; CPU iPhone OS 13_3 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/13.0.4 Mobile/15E148 Safari/604.1"
ip.of.haproxy.server - Administrator [13/Feb/2020:20:23:56 +0100] "GET /nagios/?query=programstatus HTTP/1.1" 200 1022 "https://remote.com/nagios/main.php" "Mozilla/5.0 (iPhone; CPU iPhone OS 13_3 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/13.0.4 Mobile/15E148 Safari/604.1"
Here is an excerpt from haproxy.cfg (access is always only via SSL):
Tracing the log of the HAproxy shows, that only the backend "nagios_servers" is involved (as expected)....
frontend https-in
bind *:443 ssl crt /etc/haproxy/cert/haproxy.pem
reqadd X-Forwarded-Proto:\ https
# Define hosts: criteria subdir
acl host_nagios path_beg -i /nagios
acl host_nagios path_beg /nagios
acl host_nagios path_beg /cgi-bin/nagios
.....
use_backend nagios_servers if host_nagios
.....
backend nagios_servers
server nagios local.nagios.server:443 ssl verify none check
...
### End manual additions - proxy section
Because the only difference between local and remote access seems to be the HAproxy, I suspect that something is generally wrong with the URL, the path or the header (in total) and/or what needs to be changed so that the remote access is also successful.
Any help is appreciated.