Unable to Resolve DNS on ClearOS 7.1

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Unable to Resolve DNS on ClearOS 7.1

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I have been having difficulty lately with my Clear OS 7.1 box resolving DNS,

Current config is a stand alone Server connected to another gateway. The Clear OS box has 2 NIC's with 1 disabled, and the other set to gets its IP address via DHCP from the gateway Nextgen Firewall. Recently I have been unable to resolve DNS on the ClearOS Server.

IPAddress: 192.168.0.50
DNSServer: 192.168.0.1
Interface: enp5s0
Role:LAN
Type: DHCP

[root@ldap ~]# ping 209.58.144.100
PING 209.58.144.100 (209.58.144.100) 56(84) bytes of data.
64 bytes from 209.58.144.100: icmp_seq=1 ttl=50 time=57.0 ms
64 bytes from 209.58.144.100: icmp_seq=2 ttl=50 time=95.7 ms
^C
--- 209.58.144.100 ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 1001ms
rtt min/avg/max/mdev = 57.047/76.382/95.717/19.335 ms
[root@ldap ~]# ping google.com
ping: unknown host google.com
[root@ldap ~]#

[root@ldap ~]# dig google.com

; DiG 9.9.4-RedHat-9.9.4-29.el7_2.3 google.com
;; global options: +cmd
;; connection timed out; no servers could be reached
[root@ldap ~]# dig @192.168.0.1 google.com

; DiG 9.9.4-RedHat-9.9.4-29.el7_2.3 @192.168.0.1 google.com
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;google.com. IN A

;; ANSWER SECTION:
google.com. 107 IN A 209.85.144.139
google.com. 107 IN A 209.85.144.113
google.com. 107 IN A 209.85.144.138
google.com. 107 IN A 209.85.144.101
google.com. 107 IN A 209.85.144.100
google.com. 107 IN A 209.85.144.102

;; AUTHORITY SECTION:
. 39244 IN NS b.root-servers.net.
. 39244 IN NS e.root-servers.net.
. 39244 IN NS k.root-servers.net.
. 39244 IN NS i.root-servers.net.
. 39244 IN NS h.root-servers.net.
. 39244 IN NS c.root-servers.net.
. 39244 IN NS g.root-servers.net.
. 39244 IN NS f.root-servers.net.
. 39244 IN NS d.root-servers.net.
. 39244 IN NS m.root-servers.net.
. 39244 IN NS a.root-servers.net.
. 39244 IN NS l.root-servers.net.
. 39244 IN NS j.root-servers.net.

;; Query time: 1 msec
;; SERVER: 192.168.0.1#53(192.168.0.1)
;; WHEN: Wed Sep 07 13:43:34 EDT 2016
;; MSG SIZE rcvd: 346

Not sure what I am missing if ClearOS shows my DNS as 192.168.0.1 and I am unable to resolve. but when using dig @192.168.0.1 i can resolve. Any help would be appreciated.

In IP Settings

Wednesday, September 07 2016, 05:44 PM

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Accepted Answer

Nick Howitt

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Friday, September 09 2016, 01:19 PM - #Permalink

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Got it.

Your port=0 completely disables the DNS function. See man dnsmasq.conf, then set it to 53 and reload dnsmasq.

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Accepted Answer
Nick Howitt

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Friday, December 15 2017, 09:12 PM - #Permalink
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Glad you are up and running now.

Please open a new thread for VM's, but before you do, can you search this forum for virtualbox? Remember that what works on Centos generally works on ClearOS if it can run headless so "virtualbox headless centos7" is probably a good search in the wider internet, but try to get the packages from ClearOS repos where possible.
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Ervin Bartha

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Friday, December 15 2017, 08:33 PM - #Permalink
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It seems my connection to DNS is up and running, thanks for your help, after i deleted the lines what you suggested now is ok, any suggestion how could i use VM's under the Clearos, should i start a new thread?
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Ervin Bartha

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Friday, December 15 2017, 08:28 PM - #Permalink
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Nick Howitt wrote:

How come you are using Network Manager? It is not part of the ClearOS usual configuration and I don't think it plays well with ClearOS. Is 192.168.13.1 a DNS server or your gateway or some other machine working as a DNS resolver?

Well i tried to start using VM's on the clearos host i wanted to use this guide KVM_cli_guide

Yes 192.168.13.1 is my router.

Thanks
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Nick Howitt

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Friday, December 15 2017, 08:14 PM - #Permalink
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How come you are using Network Manager? It is not part of the ClearOS usual configuration and I don't think it plays well with ClearOS. Is 192.168.13.1 a DNS server or your gateway or some other machine working as a DNS resolver?
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Ervin Bartha

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Friday, December 15 2017, 07:59 PM - #Permalink

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Hello,

please see the content for the other files:



[root@server ~]# cat /etc/resolv.conf

# Please do not edit this file.

# See http://www.clearcenter.com/support/documentation/clearos_guides/dns_and_resolver

domain darzu.lan

nameserver 127.0.0.1



[root@server ~]# cat /etc/resolv-peerdns.conf

# Generated by NetworkManager

nameserver 192.168.13.1



[root@server ~]# ls /etc/dnsmasq.d

dhcp.conf



there is no more inside there.



Thanks

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Ervin Bartha

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Friday, December 15 2017, 07:46 PM - #Permalink
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Nick Howitt wrote:

@Ervin,
It looks like you have a few extra configurations options so I guess you've been manually tinkering:
bind-interfaces listen-address=192.168.xxx.25
Seem to be manual additions. Do you need them?

well I had some issues after I had installed kvm, was not able to the default network, and I had inserted manually these additions, will start by removing them.

will post the content for the other files in a moment.

Thanks
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Nick Howitt

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Friday, December 15 2017, 06:28 PM - #Permalink
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@Ervin,
It looks like you have a few extra configurations options so I guess you've been manually tinkering:
bind-interfaces listen-address=192.168.xxx.25
Seem to be manual additions. Do you need them?

Also please give the contents of:
/etc/resolv.conf
/etc/resolv-peerdns.conf
and any file in /etc/dnsmasq.d except dhcp.conf (there probably aren't any)

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Ervin Bartha

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Thursday, December 14 2017, 07:49 PM - #Permalink
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Hello,

can check my config I got the same issue but for me it is already 53 is set for port, any other idea, what can be the issue?

[root@server ~]# cat /etc/dnsmasq.conf bind-interfaces bogus-priv cache-size=5000 conf-dir=/etc/dnsmasq.d dhcp-authoritative dhcp-lease-max=1000 domain-needed domain=daxxx.lan expand-hosts listen-address=192.168.xxx.25 no-negcache port=53 resolv-file=/etc/resolv-peerdns.conf strict-order user=nobody

Thanks for help
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Kevin Gorton

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Friday, September 09 2016, 02:53 PM - #Permalink
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That took care of it. Thanks a bunch. Like I said something simple I was just missing.
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Kevin Gorton

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Friday, September 09 2016, 01:09 PM - #Permalink
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Didn't see anything that alerted me in the dnmasq.conf

[root@ldap ~]# cat /etc/dnsmasq.conf bogus-priv cache-size=5000 conf-dir=/etc/dnsmasq.d dhcp-authoritative dhcp-lease-max=1000 domain-needed domain=gileadschool.pvt expand-hosts no-negcache port=0 resolv-file=/etc/resolv-peerdns.conf strict-order user=nobody

I did try adding DNS 8.8.8.8 and 8.8.4.4 as static overrides, and still got no resolution. Although as proven by my [code type=markup] dig @192.168.0.1 google.com[/code] line it shows the DNS server 192.168.0.1 is not the issue. I may just have to reinstall this ClearOS box was a switchover from gateway to Standalone when we got the NGS firewall in place.
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Nick Howitt

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Friday, September 09 2016, 11:18 AM - #Permalink
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Having one resolver just pointing to your external router is quite common under the assumption that if the router is down, what is the point of having a backup DNS unless you have another external connection. The router should then be configured with (or pick up from your ISP) multiple DNS addresses.

Other thoughts I have are:
- have a look at /etc/dnsmasq.conf in case of nasties
- Do some packet sniffing to see if the DNS requests exit ClearOS (and return)
- Do an arping check on the ClearOS IP (but pings by IP work so I don't see that can be an issue)
- Configure ClearOS manually with external DNS IP's, but this is bypassing rather than resolving the issue and does not help you resolve names internally
- Can IPv6 be interfering but I don't know where to start with this.
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Tony Ellis

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Friday, September 09 2016, 09:51 AM - #Permalink

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Kevin, Interesting problem :-) A comment and question or two...

What's the answer to Nick's question re whether dnsmasq is running
Having only one nameserver is not good
What device has address 192.168.0.1?
dig uses the OS resolver libraries. nslookup uses is own internal ones.
What are the contents of /etc/resolv.conf /etc/nsswitch.conf and /etc/hosts
What is output of "netstat -r"
What is the output from "nslookup -d2 google.com" ?
Here is an example of success...



[root@danda ~]# nslookup -d2 google.com

main parsing google.com

addlookup()

make_empty_lookup()

looking up google.com

setup_system()

create_search_list()

ndots is 1.

copy_server_list()

make_server(127.0.0.1)

make_server(192.168.3.17)

make_server(192.168.2.35)

lock_lookup dighost.c:3732

success

start_lookup()

setup_lookup(0x232de78)

resetting lookup counter.

cloning server list

clone_server_list()

make_server(127.0.0.1)

make_server(192.168.3.17)

make_server(192.168.2.35)

libidn_locale_to_utf8

libidn_utf8_to_ascii

using root origin

output_filter

google.com.

recursive query

add_question()

starting to render the message

done rendering

create query 0x7f1dc8275018 linked to lookup 0x232de78

create query 0x7f1dc8275240 linked to lookup 0x232de78

create query 0x7f1dc8275468 linked to lookup 0x232de78

do_lookup()

send_udp(0x7f1dc8275018)

bringup_timer()

have local timeout of 1

working on lookup 0x232de78, query 0x7f1dc8275018

sockcount=1

recving with lookup=0x232de78, query=0x7f1dc8275018, sock=0x7f1dc8277010

recvcount=1

sending a request

unlock_lookup dighost.c:3734

lock_lookup dighost.c:2410

success

send_done()

sendcount=0

check_next_lookup(0x232de78)

still have a worker

unlock_lookup dighost.c:2441

recv_done()

lock_lookup dighost.c:3163

success

recvcount=0

lookup=0x232de78, query=0x7f1dc8275018

before parse starts

after parse

printmessage()

Server:		127.0.0.1

Address:	127.0.0.1#53



Non-authoritative answer:

printsection()

output_filter

google.com.

Name:	google.com

Address: 216.58.217.206

still pending.

cancel_lookup()

check_if_done()

list empty

clear_query(0x7f1dc8275240)

clear_query(0x7f1dc8275468)

clear_query(0x7f1dc8275018)

sockcount=0

check_next_lookup(0x232de78)

try_clear_lookup(0x232de78)

destroy

freeing server 0x7f1db80008e8 belonging to 0x232de78

freeing server 0x7f1db8001108 belonging to 0x232de78

freeing server 0x7f1db8001928 belonging to 0x232de78

start_lookup()

check_if_done()

list empty

shutting down

dighost_shutdown()

unlock_lookup dighost.c:3641



done, and starting to shut down

cancel_all()

lock_lookup dighost.c:3748

success

unlock_lookup dighost.c:3778

destroy_libs()

freeing task

freeing taskmgr

lock_lookup dighost.c:3808

success

flush_server_list()

freeing commctx

freeing socketmgr

freeing timermgr

destroy DST lib

detach from entropy

unlock_lookup dighost.c:3865

Destroy the messages kept for sigchase

Removing log context

Destroy memory

[root@danda ~]#

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Accepted Answer
Nick Howitt

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Friday, September 09 2016, 08:03 AM - #Permalink
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Is dnmasq running? I tinkered recently on the machine I'm preparing for v7 and caused it to fail and the symptoms I was seeing took me a while to diagnose.
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Kevin Gorton

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Friday, September 09 2016, 01:35 AM - #Permalink

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Ha, I almost gave you those anyway. I agree it is weird. I went round and round all these. Hoping a second set of eyes points out something I am missing.



[root@ldap ~]# ifconfig  |grep ^[a-z] -A 1

enp5s0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500

inet 192.168.0.50  netmask 255.255.255.0  broadcast 192.168.0.255

--

lo: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536

        inet 127.0.0.1  netmask 255.0.0.0





[root@ldap ~]# cat /etc/clearos/network.conf

# Network mode                                                                                                    

MODE="trustedstandalone"

                                                                                                                                                              

# Network interface roles

EXTIF="enp5s0"

LANIF=""

DMZIF=""

HOTIF=""

                                                                                                                                                              

# Domain and Internet Hostname

DEFAULT_DOMAIN="gileadschool.pvt"

INTERNET_HOSTNAME="gileadschool.poweredbyclear.com"



# Extra LANS

EXTRALANS=""

                                                                                                                                                              

# ISP Maximum Speeds

ENP5S0_MAX_UPSTREAM=1530

ENP5S0_MAX_DOWNSTREAM=14620

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Accepted Answer
Nick Howitt

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Thursday, September 08 2016, 06:55 PM - #Permalink
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This is getting weirder. I can't see anything wrong yet. Is dnsmasq running ("service dnsmasq status")?

[edit]
also
ifconfig | grep ^[a-z] -A 1 cat /etc/clearos/network.conf

[/edit]
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Kevin Gorton

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Thursday, September 08 2016, 06:49 PM - #Permalink
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[root@ldap ~]# cat /etc/resolv-peerdns.conf ; generated by /usr/sbin/dhclient-script nameserver 192.168.0.1 [root@ldap ~]#
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Nick Howitt

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Thursday, September 08 2016, 06:45 PM - #Permalink
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What is the contents of /etc/resolv-peerdns.conf?
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Kevin Gorton

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Thursday, September 08 2016, 06:39 PM - #Permalink

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[root@ldap ~]# lspci -k | grep Eth -A 3

05:00.0 Ethernet controller: Broadcom Corporation NetXtreme BCM5721 Gigabit Ethernet PCI Express (rev 11)

        Subsystem: IBM eServer xSeries server mainboard

        Kernel driver in use: tg3

06:00.0 Ethernet controller: Broadcom Corporation NetXtreme BCM5721 Gigabit Ethernet PCI Express (rev 11)

        Subsystem: IBM eServer xSeries server mainboard

        Kernel driver in use: tg3

07:00.0 PCI bridge: Intel Corporation 80332 [Dobson] I/O processor (A-Segment Bridge) (rev 07)

[root@ldap ~]# arping -I enp5s0 192.168.0.1

ARPING 192.168.0.1 from 192.168.0.50 enp5s0

Unicast reply from 192.168.0.1 [00:1A:8C:58:FF:6F]  0.753ms

Unicast reply from 192.168.0.1 [00:1A:8C:58:FF:6F]  0.755ms

Unicast reply from 192.168.0.1 [00:1A:8C:58:FF:6F]  0.751ms

Unicast reply from 192.168.0.1 [00:1A:8C:58:FF:6F]  0.800ms

Unicast reply from 192.168.0.1 [00:1A:8C:58:FF:6F]  0.766ms

Unicast reply from 192.168.0.1 [00:1A:8C:58:FF:6F]  0.755ms

Unicast reply from 192.168.0.1 [00:1A:8C:58:FF:6F]  0.750ms

Unicast reply from 192.168.0.1 [00:1A:8C:58:FF:6F]  0.778ms

Unicast reply from 192.168.0.1 [00:1A:8C:58:FF:6F]  0.731ms

Unicast reply from 192.168.0.1 [00:1A:8C:58:FF:6F]  0.756ms

Unicast reply from 192.168.0.1 [00:1A:8C:58:FF:6F]  0.755ms

Unicast reply from 192.168.0.1 [00:1A:8C:58:FF:6F]  0.753ms

Unicast reply from 192.168.0.1 [00:1A:8C:58:FF:6F]  0.756ms

Unicast reply from 192.168.0.1 [00:1A:8C:58:FF:6F]  0.752ms

Unicast reply from 192.168.0.1 [00:1A:8C:58:FF:6F]  0.756ms

Unicast reply from 192.168.0.1 [00:1A:8C:58:FF:6F]  0.768ms

Unicast reply from 192.168.0.1 [00:1A:8C:58:FF:6F]  0.757ms

Unicast reply from 192.168.0.1 [00:1A:8C:58:FF:6F]  0.755ms

Unicast reply from 192.168.0.1 [00:1A:8C:58:FF:6F]  0.751ms

Unicast reply from 192.168.0.1 [00:1A:8C:58:FF:6F]  0.776ms

Unicast reply from 192.168.0.1 [00:1A:8C:58:FF:6F]  0.765ms

Unicast reply from 192.168.0.1 [00:1A:8C:58:FF:6F]  0.768ms

Unicast reply from 192.168.0.1 [00:1A:8C:58:FF:6F]  0.765ms

Unicast reply from 192.168.0.1 [00:1A:8C:58:FF:6F]  0.770ms

Unicast reply from 192.168.0.1 [00:1A:8C:58:FF:6F]  0.762ms

Unicast reply from 192.168.0.1 [00:1A:8C:58:FF:6F]  0.760ms

Unicast reply from 192.168.0.1 [00:1A:8C:58:FF:6F]  0.746ms

Unicast reply from 192.168.0.1 [00:1A:8C:58:FF:6F]  0.778ms

Unicast reply from 192.168.0.1 [00:1A:8C:58:FF:6F]  0.758ms

Unicast reply from 192.168.0.1 [00:1A:8C:58:FF:6F]  0.771ms

Unicast reply from 192.168.0.1 [00:1A:8C:58:FF:6F]  0.751ms

Unicast reply from 192.168.0.1 [00:1A:8C:58:FF:6F]  0.762ms

^CSent 32 probes (1 broadcast(s))

Received 32 response(s)

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Accepted Answer
Nick Howitt

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Thursday, September 08 2016, 05:10 PM - #Permalink
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What is the result of:
lspci -k | grep Eth -A 3 arping -I enp5s0 192.168.0.1
Ctl+c to stop the arping.
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Kevin Gorton

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Thursday, September 08 2016, 01:57 PM - #Permalink
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Nick,
Thanks you for your response,. I had it on external at one point in my troubleshooting, and was still having issues. I just tried changing the interface to external again, then reboot the box. I am still having the same issue where DNS will not resolve.
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Nick Howitt

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Wednesday, September 07 2016, 06:23 PM - #Permalink
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If it is standalone, the connected NIC's role must be External.
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