[CentOS] Re: OT: anything in CentOS 5.2 that uses opendns.com when browsing web?

Scott Silva ssilva at sgvwater.com
Fri Jul 11 23:20:33 UTC 2008

on 7-11-2008 1:48 PM Lanny Marcus spake the following:
> On 7/11/08, Scott Silva <ssilva at sgvwater.com> wrote:
> <snip>
>>> I am looking at it from the web interface. Under DHCP, for the Green
>>> Interface, for Primary DNS, it shows    If I change that
>>> to I'm done?  Other than possibly needing to change a
>>> configuration setting in the ADSL Modem, regarding DNS?  Thanks much!
>> No !!! Don't change it there. That is the IP address sent to your dhcp
>> clients
>> for them to use for dns. If you set that to, no one will find
>> anything.
>> You need to run setup either from a terminal window on the ipcop box or by
>> ssh.		
>> About halfway down is "Networking" which you select, and in that menu is
>> "Dns
>> and Gateway Settings".
>> You would set the primary dns to and if you want set the secondary
>> dns to what your primary dns was set at. You might have to play with the
>> options to have dhcp assigned red and still be able to set your nameserver
>> settings.
>> The ipcop boxes I have are all on static ip's, on either T1's or business
>> class DSL, so the settings are a little different.
> Scott: Thank you, for the above explanation!   I was able to SSH into
> the IPCop box on Port 222, very early this morning (with the syntax
> correct, that was easy) and I saw the Setup menu.
>> Whatever you do, write down the original settings of anything you change so
>> you can restore it if it horribly breaks.	
> Amen. I will write down the original settings, before I change them.
> In a tiny way, the IPCop box is a "Production" Server in our house. I
> have two (2) very demanding users: a wife and a 7 year old daughter
> and I don't want them mad.... :-) Something like not wanting your boss
> at work mad at  you....
> I am going to be working on this, when they are not using their
> Desktop boxes and I am going to do this on our Backup IPCop box, which
> actually has much better HW than the one we normally use for IPCop. If
> I can't get this to work on IPCop, that is the one I will install SME
> Server or the CentOS 4.4 Server CD on. It sounds like this is going to
> work on IPCop, which will be much easier and much faster  for me to
> get up and running properly.
> Question: Awhile ago, I got into the configuration settings for our
> ZTE ADSL Modem.
> For the change to me having my own Caching DNS Server, in the settings
> for the ADSL modem at this time, using the DNS servers at our ISP:
> Primary DNS Server
> Secondary DNS Server
> When I think I am ready to test the change I make to IPCop setting(s),
> should I set those to so I can use my own DNS Server ? Or.
> leave those spaces blank? Or, leave them as they are now? Thank you,
> very much, for your time and help, which are greatly appreciated!
> Lanny
It looks as if your ADSL modem is in NAT mode, so it is acting like a very 
simple router already. What settings does it actually have?

I think you can leave those settings alone, as they only will be used if you 
point DNS settings at the modems ip address. If you set your IPcop box at it should seek out to the root servers by itself.

As I posted earlier, you will have to poke around in the ipcop setup menu to 
get dhcp and custom DNS settings both working.

I just played with one of my test vmware ipcop images and set it to dhcp on 
our internal network (which should simulate your natted connection through 
your adsl modem) for the red interface and I was able to dig +trace google.com 
with proper answers. So it is possible to get it working unless your ISP 
blocks DNS queries to anywhere else but their own servers.

MailScanner is like deodorant...
You hope everybody uses it, and
you notice quickly if they don't!!!!

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