DNS Problem

We have a web server hosted outside of our premises (AWS) which we couldn't access internally in our office. The domain can only be accessed using the public IP of the web server or if we want to access using the domain name we can do that by configuring client computer to use the 8.8.8.8 as the primary DNS and a static IP address. The problem only occurred when we migrated our web server in the cloud. We didn't experience this problem when we have it on-prem.
CarlAsked:
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AlanConsultantCommented:
Hi,

You need to add a record to your internal DNS Server pointing to www.example.com (replacing example.com with your domain name) and the external IP address.

Thanks,

Alan.
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Mal OsborneAlpha GeekCommented:
My guess would be that you still a DNS record on your serevr pointing at the old version of the website. If you type PING WWW.EXAMPLE.COM at a command prompt, you should see the IP returned by DNS.
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CarlAuthor Commented:
Hi Alan,

I already did that (replacing it with our domain name and pointing it to our external IP address). But i am still having same problem.

Here's what i did in our SOA :

I added the ff:

example.com IN A external IP

Thanks,

Carl
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CarlAuthor Commented:
hi Mal,

the result of the ping is "Ping request could not find host "

Thanks,

Carl
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AlanConsultantCommented:
Hi,

Assuming you did a:

ping www.example.com

Open in new window

to get that error, that would imply that there is no www record in your DNS server.

Please can you re-check that the www record exists.

If it does not, please enter it, and then retry.

Thanks,

Alan.
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CarlAuthor Commented:
Hi Alan,

I just pinged the example.com without the www. I am wondering if it has something to do with our Proxy server. Because when i used Static IP and replace our internal DNS with 8.8.8.8 . I don't have any problem accessing the site using the domain name. please advise

Thanks,

Carl
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AlanConsultantCommented:
Okay, that's different.

If you ping and / or try going to www.example.com does it get you to your website?

If not, we should add that www record on your DNS server too.

I usually setup as follows:

example.com. IN A IP_Address
www.example.com. IN CNAME example.com

Open in new window


where IP_Address is the public IP that your web server responds on.

If you already have that (you did say above), then please try to ping from the Server that is running DNS (if possible) and let me know what the result of that is.

If that still doesn't work, pleas try setting the A record for www to the public IP, and see if that works, even if example.com on its own doesn't.


Alan.
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CarlAuthor Commented:
Hi Alan,

I did try to add www.example.com IN CNAME example.com then pinged from the server that is running DNS, the reply is pointing to our internal IP address which is the old IP address assigned to our on-prem web server prior to migration to cloud.

Thanks,

Carl
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AlanConsultantCommented:
Hi Carl,

What was the result after you tried setting the A record as per my previous post?

Alan.
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PerarduaadastraCommented:
Why not just search for instances of the old internal IP address and replace them with the new external IP address? This does assume that the old internal IP hasn't been assigned to another server.
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CarlAuthor Commented:
Hi Alan,

When I added the ff in our SOA:

www  IN A public IP

the result of the ping is "unknown host " from the dns server. From a client computer the result of the ping is "cannot resolve www.example.com: Unknown host"

Thanks,

Carl
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CarlAuthor Commented:
Hi Perarduaadastra,

Old internal IP was already replaced by the external public IP. But still we can't access our site using domain name.

Thanks,

Carl
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AlanConsultantCommented:
Hi Carl,

What are OS are you running on the client?

If Windows, please can you do an IPConfig /All and let us know the results.  I am wondering if your client(s) are pointing to a different DNS Server than the one that you are updating.

Also, please can you ping www.example.com from the Server that is running DNS, and see what you get there.

Thanks,

Alan.
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CarlAuthor Commented:
Hi Alan,

I am using a Windows and Mac client. When i run IPConfig /All DNS Servers is pointing to our Internal DNS Address. When i Ping(ed) www.example.com from our DNS server the result is unknown host.

Thanks,

Carl
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CarlAuthor Commented:
Hi Alan,

I did everything you instructed but i am still having same problem . Does it have something to do with our setup:

We have a local domain example.com and we have setup our web server www.example.com (hosted internally) as a redirect to our www.subdomain.example.com (hosted externally). We do not have any problem accessing www.subdomain.example.com outside of our LAN but we do have problem accessing it in our local domain.

Thanks again.

Regards,

Carl
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AlanConsultantCommented:
Hi Carl,

You haven't mentioned  www.subdomain.example.com before.

However, you said above that you have setup a record for www.example.com in your DNS server, and that even if you ping www.example.com from that machine (running the DNS server) that it still responds with 'unknown host'.

That says to me that the record(s) are not correctly setup.

Please can you re-confirm that the www record is setup for example.com in your DNS Server.

Maybe take a screen shot of the configuration and post here.

Thanks,

Alan.
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CarlAuthor Commented:
Hi Alan,

Yes i forgot to mention that what is hosted externally is a subdomain. Sorry for that.

Please see below setup:

yyy.example.com.                                             IN     A                   192.168.x.x  (Internal IP)
www                                                                    IN     CNAME        yyy.example.com

subdomain.yyy.example.com.                        IN    A                    External IP (Public IP)
www.yyy.subdomain.example.com.              IN    CNAME          yyy.subdomain.example.com.
www                                                                    IN    A                    External IP (Public IP)

; EOF

Thank you very much.

R/Carl
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AlanConsultantCommented:
Hi Carl,

So, if someone internal tries to go to www.example.com, they will get directed to 192.168.x.x.

Not sure if all of the above is one zone or two?  Are you able to do a screenshot?


Either way, if you change this (under the example.com zone):

www    IN     CNAME        yyy.example.com

to be this:

www    IN     A        External IP (Public IP)


does it work?


Alan.
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CarlAuthor Commented:
Hi Alan,

It worked! Thank you so much for your time. I really appreciate it.

The last instruction you gave solved my problem in our DNS.

Regards,

Carl
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AlanConsultantCommented:
Hi Carl,

Glad we got it sorted for you.

Don't forget to close the question.

Thanks,

Alan.
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