finding dns servers in airports/etc

[aaronhoy]

I'll often be in an airport with free wifi and get the router to give me an IP address, but name resolution will not work. Using my IP and the subnet mask I always try putting various nameservers into resolv.conf but at some airports, no matter what I do I can never resolve a name successfully. People with windows don't seem to have any problems though, so there must be some legit way of getting the airports dns server IP address. How do you do it? I've searched all over the internet looking for the answer to this question, but I just found a bunch of info about how dns works, and how to look in resolv.conf and see whats already there, but I want to know what I'm supposed to PUT there. How do I figure out the IP of the nameserver?

[mhanan]

Try adding 4.2.2.2 and 4.2.2.1

[root@manabiscuits.org]

There is so many name servers you can use. Most ISPs namerservers are able to be used by anyone.

You can use these two

vi /etc/resolv.conf

nameserver 72.236.205.150
nameserver 72.236.205.12

Those are nameserver will allow public queries.


~Edit:

There is always the chance that the Airports network will not allow dns queries to anything other than there own. In which case they should be dynamically assigned to you with you IP, bcast, network & gateway.

If the the IPs that DCHP is assigning has a local PTR record created for it than you can find the local nameservers very easily.

/sbin/ifconfig | grep 'inet addr'

dig -x $local_ip

There stdout from dig -x should report the nameserver that answered your query.

[aaronhoy]

yeah, I know I could just put in a dns server that I know of, but the problem is that as you said, before you have registered on the airport's network (which requires dns to do), you cannot access anything but the network registration proxy server. So you have to find THEIR dns server in order to resolve names initially at least so you can go through the registration page.
I can't try the command you listed right now because I'm at work and don't have root access, but I will try it when I get home. So the initial communication with the dhcp server has a built in way of giving you the local dns server address? I wonder why dhcpcd doesn't just throw that into resolv.conf right when it gets it then.

[root@manabiscuits.org]

dchpd should write to resolv.conf... and yea you can configure a dhcp server to assign many things including name servers.