Ben Zona
@btopenworld.com
|  [Servers] Can someone help with DNS resolution here?
Hi,
i am trying to setup a small network with one static IP and one mail server. so far all seems to work and i can access emails inside my lan, BUT here goes:
1. when inside the network i use local IP for the server that is 10.10.10.x. it would work fine. however if i try using mail.myserver.com it won't resolve and i will have error message connecting to the server.
2. similarly when i use laptop elsewhere outside my network i can connect via mail.myserver.com or public static IP, but not via 10.10.10.x.
Q: is it possible to have ONE email client connected to mail server regardless of my current location? as if mail.myserver.com was resolved automatically within and outside my local network?
connection type is IMAP
many thanks |
|
x30n_
Not Sure What Color Pill To Call It
Premium
join:2000-09-14
wrong turn
clubs: 
 ·AT&T U-Verse
edit:
May 1st, @02:11PM
| 1. when inside the network i use local IP for the server that is 10.10.10.x. it would work fine. however if i try using mail.myserver.com it won't resolve and i will have error message connecting to the server.
A. You need an A record for mail in your DNS server to point to your exchange servers local ip.
2. similarly when i use laptop elsewhere outside my network i can connect via mail.myserver.com or public static IP, but not via 10.10.10.x.
A. Thats because out side of your network, your internal ip isnt seen on the internet.
Q: is it possible to have ONE email client connected to mail server regardless of my current location? as if mail.myserver.com was resolved automatically within and outside my local network?
A. Once you resolve your internal dns issue and add an A record for mail, then the answer is yes. |
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fox7
join:2001-02-12
Culver City, CA
| x30n_:
Could he use a 'Host File' here to direct the mail.myserver.com to the internal IP when he is on LAN and when outside the LAN that would fail and then it would use a proper DNS??? Is that how that could work??
Thanks your reply!
fox7 |
|
x30n_
Not Sure What Color Pill To Call It
Premium
join:2000-09-14
wrong turn
clubs:
·AT&T U-Verse
| He could, it might work I dont know. I dont really deal with the host file. I have a internal dns server on my network that talks to the root servers if it isnt on my network.
But being its only one computer I dont see the harm in trying it, but when you have to start to worry about 20-30 computers, its time to hang up the use of the host file as that is just too many computers to update if you make a change. |
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aaronbav
join:2004-07-24
Atlanta, GA
| reply to Ben Zona
I use VPN to connect to my internal LAN and mail server so as not to expose my IMAP server to the outside world.
Obviously this would only work if you are using your own laptop or are at a machine where you can access/configure a VPN client. I don't beleive you mentioned what O.S. and mail server you are using - that would be helpful. |
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aaronbav
join:2004-07-24
Atlanta, GA
| Forgot to add:
I use both Mercury mail as well as SBS/Exchange 2k3. I can configure Exchange for Web access (OWA) which also works very well and is accessible from any web browser.
It is also possible to set up Mercury to be available via a Web interface by installing Squirrel Mail:
»www.netdummy.net/squirrelmail.html |
|
MattE
Obama '08
Premium
join:2003-07-20
Jamestown, NC
 ·North State Commun..
 ·Corporate Colocation
| reply to Ben Zona
said by Ben Zona :
Hi,
i am trying to setup a small network with one static IP and one mail server. so far all seems to work and i can access emails inside my lan, BUT here goes:
1. when inside the network i use local IP for the server that is 10.10.10.x. it would work fine. however if i try using mail.myserver.com it won't resolve and i will have error message connecting to the server.
2. similarly when i use laptop elsewhere outside my network i can connect via mail.myserver.com or public static IP, but not via 10.10.10.x.
Q: is it possible to have ONE email client connected to mail server regardless of my current location? as if mail.myserver.com was resolved automatically within and outside my local network?
connection type is IMAP
many thanks
1) NAT redirection issue perhaps?
2) 10.x.x.x is a non routable private IP range. Every internet router just drops those packets.
A: Yes, you need to configure mail.myserver.com in DNS with the public IP of your router, then configure (enable) internal NAT redirection for your internal clients on your router - if it supports it, then configure all your clients to use mail.myserver.com. |
|
Serbtastic
You Know How Many People I Have Buried?
Premium
join:2002-02-24
Stoney Creek
| reply to fox7
said by fox7  :Could he use a 'Host File' here to direct the mail.myserver.com to the internal IP when he is on LAN and when outside the LAN that would fail and then it would use a proper DNS??? This wouldn't work. If an entry exists in the hosts file for mail.myserver.com pointing to IP 10.10.10.x, name resolution would always succeed. The problem would be when out on the internet trying to connect to 10.10.10.x.
DNS servers are queried only when local (hosts file) name resolution fails. |
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Ben Zona
@btopenworld.com
| reply to Ben Zona
Guys, thanks all for the help.
After careful reading your posts and doing some research online and in my books, i finally accomplished the task.
I setup BIND server adding A record for the server pointing to local server address. Since the entire network consisted only of two servers + couple more laptops, i ran DNS server on my mail server. before i only had ISP nameservers which didn't resolve to local IP.
Again many many thanks for your responses. Very good board and great people!!! |
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fox7
join:2001-02-12
Culver City, CA
| reply to Serbtastic
Serbtastic:
You are confusing me. You say it would not work, but you say exactly what I said.
You: "DNS servers are queried only when local (hosts file) name resolution fails."
Me: "when outside the LAN that (the host file) would fail and then it would use a proper DNS"
I am confused by your statement.
Thanks,
fox7 |
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LLigetfa
join:2006-05-15
Fort Frances, ON | If it can "read" the host file with the entry, that does not constitute a failure. |
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MattE
Obama '08
Premium
join:2003-07-20
Jamestown, NC
·North State Commun..
·Corporate Colocation
| reply to fox7
said by fox7 :Serbtastic: You are confusing me. You say it would not work, but you say exactly what I said. You: "DNS servers are queried only when local (hosts file) name resolution fails." Me: "when outside the LAN that (the host file) would fail and then it would use a proper DNS" I am confused by your statement. Thanks, fox7 I think he meant to say it would use the IP address associated with the external FQDN.
A server not on the same LAN (abset a VPN connection) cannont talk to any of the private IP address ranges across the public internet, of which the 10.x.x.x range is a part of. |
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Serbtastic
You Know How Many People I Have Buried?
Premium
join:2002-02-24
Stoney Creek
| reply to fox7
said by fox7 :Me: "when outside the LAN that (the host file) would fail and then it would use a proper DNS" This is the part that is incorrect. Once name resolution succeeds (and in this case, because there is an entry in the hosts file it WOULD succeed) there would be no query against the configured DNS server.
Does that make sense? |
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fox7
join:2001-02-12
Culver City, CA
| Serbtastic:
Yea, I was thinking it was semantics, but I wanted to be sure. I was thinking that if the host file did not resolve to a working connection, then it would try a real DNS server. I was speculating and that is why I wanted more clarity from you. Thanks!!!
fox7 |
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x30n_
Not Sure What Color Pill To Call It
Premium
join:2000-09-14
wrong turn
clubs: | So I guess he just needs to follow my instructions I first stated to make it work.. Just hope he set up a dns server on his network. |
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Ben Zona
@btopenworld.com | reply to Ben Zona
^^^^^
I did follow your advice and set up local DNS server (bind). All works as expected. I didn't go 'hosts' file way as I wanted centralised and automated soliution and editing every next computer is not an option. |
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