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Re: Life getting to complicated?




On 23/04/2019 22:24, Lester Caine wrote:
This was an attempt to rule out the Hub6 as the problem, but with the Netgear ALSO dropping the connection not sure quite where we are ...

Sounds like it must be in BT's or Openreach's equipment. Either something wrong with the copper between you and the cabinet, a port on the equipment in the cabinet, or maybe something at the exchange.

The main problem here is that the 'problem' sites are ones running Wordpress. My own sites don't have a problem as things like cron happen independent of PHP, but it was the Wordpress scheduled events that were messed up ... along with email but that turned out to be just a corrupt IP change ...
In both cases however one accesses the dashboard via the domain name in order to get the at the management toolsc.

If you access the Wordpress dashboard via domain name then you could almost certainly access it via private LAN IP address. If you need host header to be able to reach the dashboard website on the server then either a LAN DNS server or edited hosts file (as suggested by Curtis Maurand) would allow you to do it.

As Curtis suggested, if it is too fiddly to change the script/Wordpress configuration to use local LAN IP addresses then editing your hosts file would work. Entries similar to

192.168.1.33    dashboard.myserver.com

would do it. Machines with a hosts file entry like this would skip DNS lookups and be given the internal LAN IP instead.

Alternatively you could run an internal cacheing DNS server. In this scenario, the local DNS server would contain entries for local servers which would resolve to local LAN IP addresses, and would pass on any other DNS query for the rest of the world to an upstream DNS server. For the avoidance of doubt, the local DNS server would be for internal LAN use only. You could use Pi-hole for this (I think), PFSense (as Curtis suggested) or OPNSense, or almost any other DNS server software of your choice.

There are four local servers but only 2 are visible from outside. One on each broadband line, both of which have static IPV4 addresses (but only BT support static IPV6 - Vodafone asked what it was when I requested it)

The servers are SUSE Linux, Nginx, assorted PHP-FPM for 5.x, 7.0 and 7.2 along with Firebird and MySQL for the Wordpress sites. Obviously in an ideal world all four servers would be visible from either line so that the BT one going down would not be a problem at all. Just reduced bandwidth till it's back 10 minutes later ... and I THINK the starting point for that is to have my own DNS servers on each line but now I am getting out of the comfort zone ... what I have does work the vast majority of the time so perhaps I leave it like that :)

This can get as complicated (and expensive) as you want. :-) Also it's not a PHP issue as such but, until someone tells me off, I'll comment here.

I think you could do this with round robin DNS. You could have one public-facing DNS server on each broadband line (or even the same server serving both lines). The server or servers would be the authoritative DNS server(s) for the domains in question. These servers would resolve public DNS queries for the web servers in a round robin fashion, distributing served IP addresses roughly equally between the two lines. Ideally you'd need some sort of heartbeat checking so that the DNS server(s) can detect when one of the lines or servers has gone down and remove that line's or server's public IP DNS entry from DNS responses being served out (and replace it when the server or line comes back up).

-- 
Mark Rousell