Solved

DNSSEC and Unix clients

Posted on 2014-09-04
11
289 Views
Last Modified: 2014-09-15
A company  has requested that DNSSEC be implemented in the environment.  The environment is a Windows 2008 R2 Active Directory with the DC's running DNS.  Setting up DNSSEC in DNS is relatively straightforward.  Most likely the company will also want to use IPSec with DNSSEC.   However, most of the client computers are Linux servers, so group policies are of no value here.

Would the Linux client be able to use DNSSEC?  If this is supported what are the commands on the Linux side to enable DNSSEC with IPSec?  How is this verified on the client?

I don't know if this matters but there are A records in DNS for all the Linux servers.
0
Comment
Question by:BigmacMc
  • 4
  • 4
  • 3
11 Comments
 
LVL 62

Expert Comment

by:gheist
ID: 40305733
BIND v9 implemented DNSSEC in year 2000, and support is still there.

It has nothing to do if you use IPSEC or SSL or DSL or WPA2 or none, those are just communication channels

DNSSEC validation should be enabled in DNS servers(read first line), clients are deaf and blind unless you use special DNS parsing libraries.
Part of named.conf (taken from CentOS 6)
        dnssec-enable yes;
        dnssec-validation yes;
        dnssec-lookaside auto;
        /* Path to ISC DLV key */
        bindkeys-file "/etc/named.iscdlv.key";
        managed-keys-directory "/var/named/dynamic";
that enables DNSSEC validation on BIND name server by default.
0
 
LVL 28

Accepted Solution

by:
Jan Springer earned 500 total points
ID: 40305794
If the linux box is a DNS client, then it doesn't need BIND (a DNS server).

It needs its servers specified in /etc/resolv.conf to return DNSSEC answers and it needs to not block those answers from TCP port 53.
0
 
LVL 62

Expert Comment

by:gheist
ID: 40305861
Most network impact is not "port" number, but various firealls blocking large DNS packets (4K) used by DNSSEC
0
Master Your Team's Linux and Cloud Stack!

The average business loses $13.5M per year to ineffective training (per 1,000 employees). Keep ahead of the competition and combine in-person quality with online cost and flexibility by training with Linux Academy.

 
LVL 28

Expert Comment

by:Jan Springer
ID: 40305870
And that's why I explicitly stated that traffic from TCP 53 needed to be allowed back in.

It's not just a DNSSEC thing.
0
 
LVL 62

Expert Comment

by:gheist
ID: 40305906
e.g cisco inspect will drop 4K response packet that adds 5s wait to retry with 512 byte EDNS0 request
0
 
LVL 28

Expert Comment

by:Jan Springer
ID: 40306018
i haven't configured a cisco firewall with 512 in  years.  that may be the default configuration but i've always changed it to 4096.
0
 

Author Comment

by:BigmacMc
ID: 40308654
Thanks everyone for your responses.

It is my understanding all the Linux servers are DNS clients pointing to Microsoft DNS servers, there are no Bind servers.  So my take away is etc/resolv.conf must be configured on the linux client servers to allow DNSSEC over port tcp 53.
0
 

Author Comment

by:BigmacMc
ID: 40308658
Is it safe to say that DNSSEC introduces sizable increase in DNS traffic?  That slow WAN/LAN links could possibly be impacted?
0
 
LVL 28

Expert Comment

by:Jan Springer
ID: 40308718
If your /etc/resolv.conf points to a server that cannot handle DNSSEC, then you need to consider installing a server that does or upgrade the server configuration to do so.

Regardless of the size of the traffic, if you do allow for it, then you may be blocking traffic to some zones.
0
 
LVL 62

Expert Comment

by:gheist
ID: 40309346
The traffic should have been accomodated 10 years ago.
Either way DNS does not use significant traffic.
0
 

Author Closing Comment

by:BigmacMc
ID: 40323486
Thanks for the assistance
0

Featured Post

PRTG Network Monitor: Intuitive Network Monitoring

Network Monitoring is essential to ensure that computer systems and network devices are running. Use PRTG to monitor LANs, servers, websites, applications and devices, bandwidth, virtual environments, remote systems, IoT, and many more. PRTG is easy to set up & use.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
Why the network traffic cannot pass through this IPsec tunnel? 21 109
dot directory in FreeBSD??? 4 80
Log File Creation with Header and Footer 17 96
aix unix tar error 3 67
Every server (virtual or physical) needs a console: and the console can be provided through hardware directly connected, software for remote connections, local connections, through a KVM, etc. This document explains the different types of consol…
How to set-up an On Demand, IPSec, Site to SIte, VPN from a Draytek Vigor Router to a Cyberoam UTM Appliance. A concise guide to the settings required on both devices
Windows 8 comes with a dramatically different user interface known as Metro. Notably missing from the new interface is a Start button and Start Menu. Many users do not like it, much preferring the interface of earlier versions — Windows 7, Windows X…
In this video, we discuss why the need for additional vertical screen space has become more important in recent years, namely, due to the transition in the marketplace of 4x3 computer screens to 16x9 and 16x10 screens (so-called widescreen format). …

810 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question