I've currently installed bind ver9 and its working internally without any issue, my aim is for this server to be a recursive server. I currently have 2 additional DNS servers which are facing the internet and I would like for my new internal DNS server to use these as my authoritative servers.

Please note if i configure zone forwarders before and it works just fine but then I'm unable to resolve my internal hosts as planned.

I have enabled all parameters as seen below but with no success

All help appreciated thanks in advance

//
// named.conf
//
// Provided by Red Hat bind package to configure the ISC BIND named(8) DNS
// server as a caching only nameserver (as a localhost DNS resolver only).
//
// See /usr/share/doc/bind*/sample/ for example named configuration files.
//

options {
listen-on port 53 {
127.0.0.1;
10.100.70.4;
10.100.10.4;
};
listen-on-v6 port 53 { ::1; };
directory "/var/named";
dump-file "/var/named/data/cache_dump.db";
statistics-file "/var/named/data/named_stats.txt";
memstatistics-file "/var/named/data/named_mem_stats.txt";
forwarders { 192.168.249.1; 192.168.249.3; };
allow-query {
any;
};
allow-query-cache {
any;
};
allow-recursion {
any;
};

/*
- If you are building an AUTHORITATIVE DNS server, do NOT enable recursion.
- If you are building a RECURSIVE (caching) DNS server, you need to enable
recursion.
- If your recursive DNS server has a public IP address, you MUST enable access
control to limit queries to your legitimate users. Failing to do so will
cause your server to become part of large scale DNS amplification
attacks. Implementing BCP38 within your network would greatly
reduce such attack surface
*/
recursion yes;

dnssec-enable yes;
dnssec-validation yes;

/* Path to ISC DLV key */
bindkeys-file "/etc/named.iscdlv.key";

managed-keys-directory "/var/named/dynamic";

pid-file "/run/named/named.pid";
session-keyfile "/run/named/session.key";
};

logging {
channel default_debug {
file "data/named.run";
severity dynamic;
};
};

zone "." IN {
type hint;
file "named.ca";
};

zone "mydomain.com" IN {
type master;
file "forward.mydomain.db";
allow-update { none; };
};

zone "10.100.10.in-addr.arpa" IN {
type master;
file "reverse.mydomain.db";
allow-update { none; };
};

zone "70.100.10.in-addr.arpa" IN {
type master;
file "reverse.mydomain.db";
allow-update { none; };
};

include "/etc/named.rfc1912.zones";
include "/etc/named.root.key";

I really don't quite understand what you're trying to do.
If you want this nameserver be a caching (recursive) dns for your network and also use the other 2 to resolve your "internal hosts", i.e. host of the mydomain.com zone, then your should use the following:
If that's not what you want, please try to explain better your needs.

Regards

Apologies for my poor wording of my question but at that point in time my brain was fried.

That said I found the basic error and it seems that it was nothing to do with my forwarders but the configuration.

I created the new DNS as an authoritative server which clashed with the original DNS which had the same domain name.

I know it was a noob mistake but it happens sometimes

Thanks for the help btw