If the ISP modem has a built in router, it's best to bridge the modem. Having 2 routers on the same line can cause connection problems: ...
Sounds like you are in a double NAT condition and this an effect how the DIR-880L or any router behind this ISP modem can operate correctly.
Thanks for the links !
http://www.practicallynetworked.com/networking/fixing_double_nat.htm
http://cognitiveanomalies.com/cisco-nat-how-nat-works/
The same basic functions are used in every NAT.
•NAT is the most common form of protecting the internal IP structure. Making it harder to attack the network.
•NAT enables enterprises to use less registered (public) IP addresses.
•NAT should never be confused with a firewall. It may be the same hardware but a firewall is a permit or deny traffic functioning device.
•NAT is not a firewall but a method of allowing users to change the IP source address for various reasons.
•Most common uses of NAT are port address translation and static translation.
•NAT is most commonly use with inside unregistered ( private ) addresses to some form of registered outside address when going to the www.
•Unregistered addresses rfc 1918 IP addresses are:
•10.0.0.0 – 10.255.255.255
•172.16.0.0 – 172.31.255.255
•192.168.0.0 – 192.168.255.255
... which means that both the WAN and LAN sides of your router are private networks. The upshot of this is that any UPnP and/or port forwarding you enable on your router is for naught, because incoming remote access requests never make it that far -- they arrive at the public IP address on the other device, where they're promptly discarded.
Yes, as intended I have 2 separated private network segments using 2 routers with NAT and SPI and separate address spaces.
Voip and UPNP is not an issue for me; firewalled separation of networks is.
My "untrusted" devices are plugged into the "outer" network segment (ie attached to the ISP's router, ie an internal DMZ) and cannot see any devices plugged into the inner network (ie behind the second NAT'd router), whereas devices plugged into the inner network can in part see devices in the outer network enough for me.
Multiple port-forwarding has also worked with previous router combinations.
This should not affect DNS manually entered into the inner router settings (in my case the DIR-880L) ?
DNS relay worked with my old DIR-655.
DNS server addresses manually entered into each of the routers should work.
Happy to be corrected
If I was to make a wild guess, it'd be maybe the 880L is somehow swapping using DLINK's own DNS servers (there is a config settings for that somewhere). If I find time, I wonder if I can network sniff it somehow. As always, I am not a network person and may be completely and utterly wrong on all counts ... let me know !
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Topic: DIR-880L does not use the DNS servers manually entered (Read 11152 times)