FAQ
Hello all,

I am trying to configure a subdomain DNS server on a Cent OS 5.1 - for
my lab. Brief configuration:

Lab machine ---> 192.168.17.2 (should respond to DNS queries from
hosts in 192.168.16.0/20 network)

1. I would also like to forward any queries outside the above network
to our corporate domain (no firewalls between our 192.168.16.x network
and the corporate network. The domain server is: dns.company.com
with an IP of 10.100.1.2 (255.255.255.0).

2. What I have configured is:

192.168.17.2 --> myhost.lab.company.com
10.100.1.2 --> dns.company.com

3. Installed the dns bind 9 in myhost and set basic configuration via
the system-config-bind GUI. My configuration file specific to my
setup there is:

cat lab.maxiscale.com.db
$TTL 1H
@ SOA myhost.lab.company.com.
root.myhost.lab.company.com. ( 2
3H
1H
1W
1H )
NS myhost.lab.company.com.
qaserver2 A 192.168.17.3
qaserver1 A 192.168.17.1
myhost A 192.168.17.2

=================

The rest of the DNS/Bind records were based upon the auto-generated
files from the Bind GUI Config tool.

3. I also changed myhost's resolv.conf to reflect the following:

search lab.mycompany.com
192.168.17.2
search mycompany.com
10.100.1.2

======

PROBLEM:

1. When I am in myhost.com, I can perform:
a. nslookup hostname (to any host within 192.168.x and 10.100.x networks)
b. nslookup ip to anyhost wtihin both networks.

2. When I am in one of the hosts within 192.168.x aside from
myhost.com (for example, qaserver1 or qaserver2):

a: SUCCESS to nslookup hostname to any host within BOTH networks.
b. FAILS to nslookup ip (reverse nslookup) to anyhost within the
10.100.x network.

this is the error I get:

nslookup 10.100.1.2
Server: 192.168.17.2
Address: 192.168.17.2#53

Non-authoritative answer:
24.1.100.10.in-addr.arpa name = dns.company.com.

Authoritative answers can be found from:
. nameserver = e.root-servers.net.
. nameserver = f.root-servers.net.
. nameserver = g.root-servers.net.
. nameserver = h.root-servers.net.
. nameserver = i.root-servers.net.
. nameserver = j.root-servers.net.
. nameserver = k.root-servers.net.
. nameserver = l.root-servers.net.
. nameserver = m.root-servers.net.
. nameserver = a.root-servers.net.
. nameserver = b.root-servers.net.
. nameserver = c.root-servers.net.
. nameserver = d.root-servers.net.
a.root-servers.net internet address = 198.41.0.4
b.root-servers.net internet address = 192.228.79.201
c.root-servers.net internet address = 192.33.4.12
d.root-servers.net internet address = 128.8.10.90
e.root-servers.net internet address = 192.203.230.10
f.root-servers.net internet address = 192.5.5.241
g.root-servers.net internet address = 192.112.36.4
h.root-servers.net internet address = 128.63.2.53
i.root-servers.net internet address = 192.36.148.17
j.root-servers.net internet address = 192.58.128.30
k.root-servers.net internet address = 193.0.14.129
k.root-servers.net has AAAA address 2001:7fd::1
l.root-servers.net internet address = 199.7.83.42

=====

I must be missing something stupid and apparent .... any help would be
greatly appreciated!!!

:)

thanks in advance!


--
best,

Vince

Search Discussions

  • Mouss at Mar 21, 2008 at 7:59 pm

    vincenzo romero wrote:
    Hello all,

    I am trying to configure a subdomain DNS server on a Cent OS 5.1 - for
    my lab. Brief configuration:

    Lab machine ---> 192.168.17.2 (should respond to DNS queries from
    hosts in 192.168.16.0/20 network)

    1. I would also like to forward any queries outside the above network
    to our corporate domain (no firewalls between our 192.168.16.x network
    and the corporate network. The domain server is: dns.company.com
    with an IP of 10.100.1.2 (255.255.255.0).

    2. What I have configured is:

    192.168.17.2 --> myhost.lab.company.com
    10.100.1.2 --> dns.company.com

    3. Installed the dns bind 9 in myhost and set basic configuration via
    the system-config-bind GUI. My configuration file specific to my
    setup there is:

    cat lab.maxiscale.com.db
    $TTL 1H
    @ SOA myhost.lab.company.com.
    root.myhost.lab.company.com. ( 2
    3H
    1H
    1W
    1H )
    NS myhost.lab.company.com.
    qaserver2 A 192.168.17.3
    qaserver1 A 192.168.17.1
    myhost A 192.168.17.2

    =================

    The rest of the DNS/Bind records were based upon the auto-generated
    files from the Bind GUI Config tool.

    3. I also changed myhost's resolv.conf to reflect the following:

    search lab.mycompany.com
    192.168.17.2
    search mycompany.com
    10.100.1.2
    what's this? should be:

    search lab.mycompany.com mycompany.com
    server 192.168.17.2
    server 10.100.1.2
    ======

    PROBLEM:

    1. When I am in myhost.com, I can perform:
    a. nslookup hostname (to any host within 192.168.x and 10.100.x networks)
    b. nslookup ip to anyhost wtihin both networks.

    2. When I am in one of the hosts within 192.168.x aside from
    myhost.com (for example, qaserver1 or qaserver2):

    a: SUCCESS to nslookup hostname to any host within BOTH networks.
    b. FAILS to nslookup ip (reverse nslookup) to anyhost within the
    10.100.x network.
    you did not create the reverse zone. the zone file should contains
    something like

    $TTL 1H
    @ SOA myhost.lab.company.com.
    root.myhost.lab.company.com. ( 2
    3H
    1H
    1W
    1H )
    NS myhost.lab.company.com.


    3 IN PTR qaserver2.lab.company.com.
    1 IN PTR qaserver2.lab.company.com.
    2 IN PTR myhostA.lab.company.com.

    WARNING. don't forget the trailing dot (...lab.company.com. with a dot
    at the end).

    you must tell you bind that it is authoritative for this zone. so in
    named.conf, add


    zone "17.168.192.IN-ADDR.ARPA" {
    type master;
    file "192.168.17.db";
    };

    where 192.168.17.db is the name of the zone file.

    A good reference for DNS is
    http://www.zytrax.com/books/dns/
  • Vincenzo romero at Mar 24, 2008 at 7:57 pm

    where 192.168.17.db is the name of the zone file.

    A good reference for DNS is
    http://www.zytrax.com/books/dns/
    thank you for the reference and response... I have also checked the
    above and reviewed it.... and attempted to follow the configuration
    file samples; however I noticed in CentOS is that I either:

    - use the Bind Configuration Tool
    or
    - configure DNS manually (byhand, hence the above reference should be followed).

    As I am a newbie, I attempted to configure using the Bind
    Configuration Tool (GUI) that automatically creates my records files;
    The questions I have are:

    1. Is there some URL or reference that has a "step-by-step-DNS
    configuration" based upon the Bind configuration Tool (GUI)? the
    manuals is not a cookbook and could potentially cause newbies to make
    mistakes. the HOW-TO-FORGE document - does NOT show step-by-step but
    only shows how to INSTALL bind. ... If anyone is aware of such a
    link, I would appreciate pointers to where.

    2. I did not seem to find a place to configure my /etc/resolv.conf -
    do I configure this from the Network Manager? Again, I feel that I
    should configure all via GUI since it seems that if I configure
    sometimes by editing files or by GUI, then the configuration gets
    messed up.

    thanks in advance,
  • Robert Moskowitz at Mar 24, 2008 at 8:17 pm

    vincenzo romero wrote:
    where 192.168.17.db is the name of the zone file.

    A good reference for DNS is
    http://www.zytrax.com/books/dns/
    thank you for the reference and response... I have also checked the
    above and reviewed it.... and attempted to follow the configuration
    file samples; however I noticed in CentOS is that I either:

    - use the Bind Configuration Tool
    or
    - configure DNS manually (byhand, hence the above reference should be followed).

    As I am a newbie, I attempted to configure using the Bind
    Configuration Tool (GUI) that automatically creates my records files;
    The questions I have are:
    Use webmin. (webmin.com). I am an old hand at BIND and use webmin
    regularly....
    1. Is there some URL or reference that has a "step-by-step-DNS
    configuration" based upon the Bind configuration Tool (GUI)? the
    manuals is not a cookbook and could potentially cause newbies to make
    mistakes. the HOW-TO-FORGE document - does NOT show step-by-step but
    only shows how to INSTALL bind. ... If anyone is aware of such a
    link, I would appreciate pointers to where.

    2. I did not seem to find a place to configure my /etc/resolv.conf -
    do I configure this from the Network Manager? Again, I feel that I
    should configure all via GUI since it seems that if I configure
    sometimes by editing files or by GUI, then the configuration gets
    messed up.

    thanks in advance,
    _______________________________________________
    CentOS mailing list
    CentOS@centos.org
    http://lists.centos.org/mailman/listinfo/centos

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