does rhl 9 support dynamic updates of A and PTR records ?

[Maaz]

Hi Experts,
I have win2k3 server running dns, and dhcp.

test.com domain
I have enabled/configured dynamic update for the test.com (nonsecure and secure).

Dhcp server is configured to "Always Dynamically update DNS A and PTR records.".. this simply means that if client doesnt ask to update its A and PTR records in dns, DHCP server itself update the the dns zone.

all winxp, and win2k clients A and PTR records are dynamically/automatically update in DNS, but all linux(redhat 9) dhcp clients records are not dynamically/automatically update.

is it win2k3 dhcp server issue ? or its a rhl 9 client's issue ?

Regards
Maaz

[Sergejs Svitnevs]

You need to configure the DHCP server to dynamically register the DNS entries for those that don't request it.

To modify this setting, select also the "Dynamically update DNS A and PTR records for DHCP clients that do not request updates(for example, clients running Windows NT 4.0)" check box, which is located in Properties on the DNS tab on your DHCP server.

Regards,
Sergejs

[Maaz]

Dear Sergejs Svitnevs many thanks for the help.
I even select the "Dynamically update DNS A and PTR records for DHCP clients that do not request updates(for example, clients running Windows NT 4.0)" check box, ocated in Properties on the DNS tab on DHCP server,.. but still rhl9 A and PTR records are not automatically update/add in the appropriate zone(s).

Regards
Maaz

[Sergejs Svitnevs]

1. Make sure that your linux client is getting it's IP address from your DHCP server.

2. Does your DNS server accept non-secure updates?

Regards,
Sergejs

[Stuart Browne · Accepted solution]

I would assume your RH9 box is using 'dhclient' as the DHCP client, as against 'dhcpcd' or 'pump'.

If that's the case, read 'dhclient.conf', in particular the section on 'DYNAMIC DNS'.

It states, simply, that you need to add the 3 lines:

send fqdn.fqdn "grosse.fugue.com.";
send fqdn.encoded on;
send fqdn.server-update off;

to your '/etc/dhclient-.conf' (or create it if it doesn't exist. The '-' is part of the 'ifup' routine).

If using 'pump' or 'dhcpcd', read their associated documentation for information on DNS updates.

[Maaz]

Dear Sergejs Svitnevs,
1. YES linux client is getting ip adres from DHCP server.

2. YES DNS server is configured to accept the non-secure updates.

1. Make sure that your linux client is getting it's IP address from your DHCP server.

Dear Stuart Browne, I'll reply u tomorow on monday.. i m at home now.

Regards
Maaz

[Maaz]

Thanks Stuarte Browne.. as per your instruction I create /etc/dhclient-eth0.conf, and add three lines:

send fqdn.fqdn "rhlbox1.test.com.";
send fqdn.encoded on;
send fqdn.server-update off;

and its working quite smoothly/fine.
One more thing there is no need to configure the win2k3 DHCP server to "Dynamically update DNS A and PTR records for DHCP clients that do not request updates(for example, clients running Windows NT 4.0)", .. just simply create the /etc/dhclient-.conf file.

Here is one question again.
in /etc/dhclient-eth0.conf
.
send fqdn.server-update off;
the line above cause the A and TXT records registerd in the zone. Plz le me know what are the TXT records... and their usage/implementation... when and where TXT records are used ?


Regards
Maaz

[Stuart Browne]

Ok. I'd assume that if the DHCP server wasn't allowing DNS updates, then the DNS wouldn't get updated, even if the client requested them... But I've not use W2K3 (or any windows) DHCP server before.

As for zone records..

A = Address record. Either an A or CNAME record (pointing to another A record) are required for a name to resolve into an IP address.

TXT = Text record. These are not required, but are generally used to make public notes about a given host.

You've also got records such as:

HINFO : Generally used to publically show information about hardwre (but not often)
CNAME : A-record aliasing
SOA : Start-of-zone-authority, sets TTL etc.
MX : Mail Exchanger targets
NS : Name server listings for domain

And specficially for reverse zones (IP-to-Name):

PTR : Reverse pointer record

Anyway.. (yay RFC1035!)..

For your purposes, youd efinatly want A records (and if possible PTR records) updated. The TXT is probably just saying when it was last updated and by who, but isn't required. It won't hurt anything though.

[Maaz]

Ok here is the summary

Just install dhcp(win2k3) server and configure the scope, and scope options, like default gateway's ip, dns server's ip, domain name etc.

Nothing additional is required to support the dynamic updates for the rhl9 clients...i.e no need to enable/check the "Dynamically update DNS A and PTR records for DHCP clients that do not request updates(for example, clients running Windows NT 4.0)" check box, which is located in Properties on the DNS tab of the DHCP server.


just have to create the /etc/dhclient-.conf file(for details see the stuart post above), and then
ifdown ethx; ifup ethx

But here is one interesting thing i found i.e if we explicitly disable the Dynamic update feature in win2k3/win2k dhcp server(By default in win2k/win2k3 the dhcp server is configured to support the dynamic updates..for the clients that request to update A and PTR records), and the rhl9 client is properly configured.. even then A, and TXT records will be registerd, but the PTR records will not. But it must be clear.. that win2k3/win2k dhcp servers are by default configure to support the dynamic updates.

Once again Many Thanks Dear Sergejs Svitnevs and Stuart Browne for the help/support.

Regards
Maaz