DNS Query

[adduxi]

Regarding the recent scare about some routers having their DNS entries changed, I was wondering about the following.
If you have static IP entries on a PC, including DNS entries, and you also have DNS entries in the router, which one does the PC actually use when doing a lookup?
So, if the router entries were changed, does it matter to the PC?

Thoughts, opinions.......

[dev]

the one on the PC, the router's DNS settings should only be used by a PC when it requests an IP off the router (via DHCP)

[adduxi]

Thanks for the quick reply.
Good to know there are always people who know stuff ........

[Jon T]

Originally Posted by dev

the one on the PC, the router's DNS settings should only be used by a PC when it requests an IP off the router (via DHCP)

Most(if not all routers) will act as a DNS proxy, where the PC uses the router as a DNS server and then the router passses the request on to the ISP(or whatever it's got set as it's DNS addreses. Whether your PC uses the routers DNS proxy depends on if you've got your primary DNS nameserver set to the IP of your router. This is true whether your IP is allocated by DHCP, or you have manually set a static address.

Even on a small home network you should always dns through your router as this can avoid un-necessary DNS lookups, for example I go to news.bbc.co.uk, the router has to pass the query on to external DNS resolution, my partner then goes to news.bbc.co.uk on her PC, this time the router answers the DNS request directly as it already knows the answer.

[dev]

Originally Posted by Jon T

Most(if not all routers) will act as a DNS proxy, where the PC uses the router as a DNS server and then the router passses the request on to the ISP(or whatever it's got set as it's DNS addreses. Whether your PC uses the routers DNS proxy depends on if you've got your primary DNS nameserver set to the IP of your router. This is true whether your IP is allocated by DHCP, or you have manually set a static address.

Even on a small home network you should always dns through your router as this can avoid un-necessary DNS lookups, for example I go to news.bbc.co.uk, the router has to pass the query on to external DNS resolution, my partner then goes to news.bbc.co.uk on her PC, this time the router answers the DNS request directly as it already knows the answer.

i would have thought the router would only be doing the DNS queries if the settings on the PC set it to, i'd hate a router that was intercepting traffic and doing things itself and i know both linksys routers i've had haven't done this.

[Jon T]

Originally Posted by dev

i would have thought the router would only be doing the DNS queries if the settings on the PC set it to, i'd hate a router that was intercepting traffic and doing things itself and i know both linksys routers i've had haven't done this.

that's what I said.

"Whether your PC uses the routers DNS proxy depends on if you've got your primary DNS nameserver set to the IP of your router"

If your PC(or other TCP/IP device) has it's own DNS servers specified(and the adresses are not that of your router), then your router will play no part in DNS resolution at all.

[dev]

Originally Posted by Jon T

that's what I said.

"Whether your PC uses the routers DNS proxy depends on if you've got your primary DNS nameserver set to the IP of your router"

If your PC(or other TCP/IP device) has it's own DNS servers specified(and the adresses are not that of your router), then your router will play no part in DNS resolution at all.

missed that out ><. So what i said originally was correct. The settings in the router will only be used if you are using DHCP, otherwise setting a static IP requires you to manually put them in, and so the ones you put in will be used.

[Jon T]

Originally Posted by dev

missed that out ><. So what i said originally was correct. The settings in the router will only be used if you are using DHCP, otherwise setting a static IP requires you to manually put them in, and so the ones you put in will be used.

Yep