SME Office Centro Business <-> NAT <-> DNS <-> DHCP

[cdufour]

Hello,

On my SME Office Centro Buisness router (FW 7.10.12), I have setup "Port Forwarding" (NAT) for various LAN services (HTTP/S, SMTP, IMAP, SSH, etc.) which reside in a *separate IP segment* (with an *appropriate static route entry*).

It works perfectly from the Internet.

On the other hand, those services are not accessible from the router (LAN) IP segment. It comes done to:

 - "Port Forwarding" and corresponding "Firewall Rules" apparently do not allow "NAT Loopback", iow. access to services via their *public* IP adress from the LAN segment (REF: https://en.wikipedia.org/wiki/Network_address_translation#NAT_loopback)

 - Centro Business router does not allow to change the DNS server(s) setting (!!!???!!!); iow. there is no way for LAN guests to retrieve the "internal" IP addresses for the NAT-ted services from an "internal" DNS server (which I do have available)

 - Centro Business router does not allow DHCP relaying, which would allow my DHCP server in my *separate*/routed IP segment to provide the correct DHCP settings - incl. DNS server(s) IP addresses - to clients (REF: https://en.wikipedia.org/wiki/Dynamic_Host_Configuration_Protocol#DHCP_relaying)

My question is thus: how do I allow my Centro Business clients to reach my own NAT-ted services ?

(one would assume that a SME product - especially more so with a static public IP address which is paid for -  would not prevent its customers to setup their internal IT however they want)

Thanks for your feedback and best regards,

Cédric

[LuanaC]

Hello

The functions you mentioned such as “DHCP-relay” and “NAT-loopback” are not available at the Centro Business / Centro Business 2.0 interface. There are two possible workarounds: Activate the IP-Forwarding at the Centro Business Interface and configure the functions at your own firewall. For higher requirements  we suggest products like “Business internet standard” with Cisco-hardware.

Best regards

LuanaC

[cdufour]

Hello,

Thank you for your reply.

I can understand "DHCP-relay" is a rather advanced "enterprise-level" feature.

"NAT-loopback", on the other hand, has been available in all cheap off-the-counter routers I've ever laid my hands on. It comes as a natural complement to any device that does NAT (and usually takes no more than an additional configuration line to be enabled).

Best