In AWS VPC, I am associating the following as DHCP
Domain name server: 10.*.*.2 (VPC DNS)
Domain Name: ec2.internal privatedomain_1.com privatedomain_2.com publicdomain.com
Due to which the hostname is getting set up as ip-10-5-*-*.privatedomain_1.comprivatedomain_2.compublicdomain.com
the above is the combination of all 3 Domains names given in DHCP.
The reason to add the domains to DHCP is to only effect /etc/resolv.conf and not the hostname but it is not working as expected, also it is adding a combination of these entries in `/etc/resolv.conf as well
# cat /etc/resolv.conf
# Generated by NetworkManager
search ec2.internal privatedomain_1.com privatedomain_2.com publicdomain.com
privatedomain_1.comprivatedomain_2.compublicdomain.com
nameserver 10.*.*.2
I have tried using the preserve hostname document provided by AWS and cloud-init
https://aws.amazon.com/premiumsupport/knowledge-center/linux-static-hostname-rhel-centos-amazon/
How do I stop cloud-init from overwriting my hostname on AWS (CentOS)
https://cloudinit.readthedocs.io/en/latest/topics/modules.html#set-hostname.
but these didn't work out, Any suggestions?
Related
When I connect to a VPN using open connect, the docker containers that run afterwards have the ability to use DNS but the host machine itself does not.
If I look at the contents of /etc/resolv.conf in the containers, the file has the DNS servers in them, but the file on the host machine does not.
From Containers:
# This file is managed by man:systemd-resolved(8). Do not edit.
#
# This is a dynamic resolv.conf file for connecting local clients directly to
# all known uplink DNS servers. This file lists all configured search domains.
#
# Third party programs must not access this file directly, but only through the
# symlink at /etc/resolv.conf. To manage man:resolv.conf(5) in a different way,
# replace this symlink by a static file or a different symlink.
#
# See man:systemd-resolved.service(8) for details about the supported modes of
# operation for /etc/resolv.conf.
nameserver 10.x.x.x
nameserver 10.x.x.x
search university.liberty.edu liberty.edu
(I have replaced the actual addresses)
From the host:
# Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8)
# DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN
# 127.0.0.53 is the systemd-resolved stub resolver.
# run "systemd-resolve --status" to see details about the actual nameservers.
nameserver 127.0.0.53
search university.liberty.edu liberty.edu
When I use anyconnect instead of openconnect, the containers do not have dns but the host machine does. Everyone on my development team has had identical results. We're on Linux Mint 19.
I added the DNS addresses in the IPv4 tab of the Network Manager in network settings.
Does anyone have any suggestions as to what I need to do to have DNS available to the host machine and the containers at the same time?
Update:
When I connect to VPN using Cisco AnyConnect, the link from /etc/resolv.conf to /run/resolvconf/resolv.conf is maintained. The result of this is that docker containers run afterward DO NOT have access to DNS. When I connect to VPN using Cisco's openconnect, the link from /etc/resolv.conf is broken and replaced, presumably by open connect. The result of this is that the docker containers are happy using DNS, but my host machine cannot.
I have a domain bought from GoDaddy. I have set the custom name servers this
ns1.domain.com
ns2.domain.com
and set hostname
ns1 52.70.xxx.xxx(aws ip)
ns2 52.70.xxx.xxx (aws ip)
As I have installed WHM in my amazon aws instance. so In WHM, I have created an account and then went to Edit DNS Zone and added A records. These are my settings there
But I don't see my domain working and I am not able to see Cpanel of the domain as well.
what am I missing?
Please follow these steps to integrate your domain into whm and create a cpanel.
Create an account in WHM by going into Account Functions->Create Account: enter your domain here
Go to DNS Functions->Edit Dns Zone and click your domain and add A records
Then Go to Godaddy or any Company where you have purchased your domain and edit the name servers. For example if the nameservers you set in whm dns were ns1 and ns2 then same add here(e.g godaddy). In your case it would be
ns1.domain.com
ns2.domain.com
Click Manage hostname in Godaddy and add
ns1 52.70.xxx.xxx(aws ip)
ns2 52.70.xxx.xxx (aws ip)
Your domain should be working here. But If still It didn't work then
Check if ports(2087,2083,53,2095) are open. Check it from the terminal
nmap -Pn -sT 172.31.iphere --reason -p 2087,2083,2095,53
If any port is closed. Open it from the aws by going into Security Firewall.
Please note, 2083 and 2095 will always show as closed from external port scans as these ports are only opened publicly based on valid sessions established from within the cPanel server.
Verify again if your DNS port is opened
nmap -Pn -sT 172.31.iphere --reason -sU -p 53
After opening all the ports rebuilt your DNS configuration on the server by typing these commands on the terminal
cpanel root#9449099 /var/named]cPs# cd /etc
cpanel root#9449099 /etc]cPs# mkdir /root/cptechs
cpanel root#9449099 /etc]cPs# mv named.conf /root/cptechs
cpanel root#9449099 /etc]cPs# mv rndc.* /root/cptechs
cpanel root#9449099 /etc]cPs# /scripts/rebuilddnsconfig
Hope it helps
Are you using Nameservers for domain.com that are ns1/2.domain.com?
If this is the case the domain will not be able to resolve without adding the ns1/2. as "Child Nameservers".
You can create that for your domain through GoDaddy https://uk.godaddy.com/help/add-my-own-host-names-as-nameservers-12320
Alternatively - you can post your domain so we can troubleshoot it if it's a DNS issue.
How do I exclude DNS from the DHCP lease request on a Raspberry Pi?
I tried updating /etc/resolv.conf but it's reset after a while.
Reason: I am on a home network, and the home router uses itself as the DNS server, but the router's DNS service isn't working properly sometimes.
Most of the answers didn't work for me, but I found that this worked:
sudo vi /etc/dhcpcd.conf
Added a line (note that there is no comma):
static domain_name_servers=8.8.8.8 8.8.4.4
And unplugged and replugged my ethernet cable, which updates the resolver...
cat /etc/resolv.conf
Now shows:
# Generated by resolvconf
domain example.com
nameserver 8.8.8.8
nameserver 8.8.4.4
This also a better way to fix the problem where changes to /etc/resolv.conf are lost on reboot.
I asume the problem is, that the dhcpclient is getting new information about DNS servers with every dhcp-renewal. Add this line into /etc/dhcp/dhclient.conf:
option domain-name-servers 192.168.1.8, 8.8.8.8, 8.8.4.4
Of course you should replace the ip-addresses with the ones from your demanded DNS server. Probably restart the according service.
I am working on RHEL 6.3, the IP address of this server is 172.xxx.xxx.xx and hostname is build01.xxx.com
I have a DNS entries of client server, I have configured that in /etc/sysconfig/network-scripts/ifcfg-eth0 and in /etc/resolv.conf
[root#build01 ~]# cat /etc/resolv.conf
search 100.xxx.x
nameserver 203.xxx.xxx.xxx ##Primary DNS
nameserver 203.xxx.xxx.xxx ###Secondary DNS
[root#build01 etc]# cat /etc/hosts
127.0.0.1 localhost localhost.localdomain localhost4 localhost4.localdomain4
172.xxx .xxx.xx build01.xxx.com build01
[root#build01 ~]# hostname
build01.xxxx.com
My issue is when I hit the URL with hostname(buil01.xxx.in) it does not work, but it works with IP (172.xxx.xxx.xx)
This is the error which i get in browser if I type hostname
Host Not Found
**DNS error (the host name of the page you are looking for does not exist) or Server did not accept the connection.
Please check that the host name has been spelled correctly.**
Internet works in this machine only issue is with hostname
Please help me what I am missing to configure
Thanks
Roopa
The search line in resolv.conf should list the local domain. So change:
search 100.xxx.x
to:
search xxx.com
Actually you should also change search to domain. For more information have a look at man resolv.conf.
I have a centOS system(embedded and has very binaries) with the following /etc/hosts.
$cat /etc/hosts
127.0.0.1 localhost localhost
Also the host is assigned a DNS server which returns some invalid IP for the domain name lookup of localhost. But I cannot avoid a connection to this DNS due to some network restrictions.
My question is, when I already have a valid /etc/hosts file why is the system querying the DNS for localhost? And how can I stop that?
Any help would be greatly appreciated.
Check that you have files listed before dns for the hosts entry in /etc/nsswitch.conf.
[me#home]$ grep "^hosts" /etc/nsswitch.conf
hosts: files dns
If dns comes first, then your system will always query DNS to resolve hostnames before falling back to /etc/hosts.