[cs615asa] Can't connect to DNS server

[Tejas]

I got it to work!! Found a very similar post finally on AWS support. It 
seems if you are running RH6 AMI theres iptables firewall service that 
you have to stop. No way I would have known this without this post. Hope 
this helps people.

https://forums.aws.amazon.com/thread.jspa?messageID=215098



On 03/24/2012 03:56 PM, Jan Schaumann wrote:
> Tejas<tnadkarn at stevens.edu>  wrote:
>
>> For testing I opened all TCP/UDP/ICMP ports for the instances I'm using.
>> I can ping as I said and I was able to telnet into SHH port 22 on the
>> DNS server from the host without issue. I can traceroute from the host
>> to the DNS and it all looks good.
>>
>> However any attempt on port 53 is refused. This leads me to believe it's
>> something with the local DNS process since I have a single AWS rule for
>> both port 22 and 53 so I don't believe it's a firewall issue.
> What a wonderful occasion to use tcpdump(1) to see what's happening! :-)
>
> If you do indeed have UDP/53 open to the public on your AWS instance,
> then you should also be able to query it from any other host (say,
> lab.cs.stevens.edu).  Does that work?  If not, what does tcpdump(1) tell
> you?  (Note: it's most useful for you to run tcpdump(1) on both ends and
> see what packets are coming through, if any.)
>
> -Jan
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