First I will discuss what DNS is. Sorry if I have gone over this before, but considering its the issue at hand, I think it stands repeating. Domain Name System(DNS) is a way for a internet device to know how to get to a certain part of the internet, like of like a internet phone book. Just like the phone book matches up names with phone numbers, your DNS server matches up website names, or domains, with their internet number, or internet protocal(IP).
Ok, well the good news is it happens once a night. And I have lots of trick up my sleave. Technically, you don't "need" dns. You can program your host files manually. The thing is there are several different methods to use DNS. We may have to try each way, and see which way works best for you.
Router:
1. Leave to default. All DNS querys are processed and sent to the DNS aquired when the router booted up.
2. A DNS can be manually entered into the router. Requests are still processed by the modem and thus delayed.
3. Advanced DNS can be enabled. This uses a static DNS beloning to the OpenDNS domain, a 3rd party DNS system. Simular over-all to 2, just Open-DNS may be better and/or quicker then your ISP's DNS.
4. A OpenDNS can be manually entered in. This is like 3, except you can choose which OpenDNS server to us, and might be able to choose one that is closer.
5.DNS Relay can be enabled. This allows the router to send requests directly to the DNS on file. This DNS can be any of the 1-4 options. This is good if your ISP and/DNS gives a lower priority to DNS related ICMP traffic.
PC:
1. Obtain DNS Server Automaticallly. Gets what ever DNS the router provides. (Can't be used if Static IP)
2. Set a static DNS. Sends traffic to DNS you set, so can conflict with DNS Relay on the router, if you also have a static DNS set on the router that is different then the static DNS set on the PC. In this way, a static DNS on the PC doesn't work real well with Advanced DNS and DNS relay, since the router is trying to send it one way, and the PC is demanding another way.
3. Static OpenDNS server.
4. Disable DNS Service. Then manually program the Domain > IP in your computers Host files.
5. Set up a DNS server on your LAN. I think that is beyond your need, and beyond the scope of this forum.
Theres probably some methods I am missing too, and theres a ton of combining those methods. Some of those methods don't well together, as discussed. Start off by replying with what you have already tried. I will start you off with two procedures to try after, and we will take it nice and slow. If you have the time, I have the time. And each time, we will have to wait a day or two, to feel out how it worked.