I use static IP adresses on all systems in the network, including 3 ClearOS7 systems.
After changing ISP, the new router would joyfully connect all Windows systems to the Internet, but the 3 ClearOS systems returned DNS Failure problems.
These problems went away after changing the network cards from "static" to "DHCP". However, nothing seems wrong with Gateway or DNS addresses, and my Windows computers run just fine, so this is something I don't understand. Running ClearOS systems with DHCP is fine for a while, but I would like to solve this problem eventually. The new ISP router can issue fixed IP-adresses to MAC-addresses. but these fixed IP's seem to be overruled by ClearOS (or by the network cards) if in DHCP-mode.
After changing ISP, the new router would joyfully connect all Windows systems to the Internet, but the 3 ClearOS systems returned DNS Failure problems.
These problems went away after changing the network cards from "static" to "DHCP". However, nothing seems wrong with Gateway or DNS addresses, and my Windows computers run just fine, so this is something I don't understand. Running ClearOS systems with DHCP is fine for a while, but I would like to solve this problem eventually. The new ISP router can issue fixed IP-adresses to MAC-addresses. but these fixed IP's seem to be overruled by ClearOS (or by the network cards) if in DHCP-mode.
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Accepted Answer
You have a NIC with a known issue. The RTL8111/8168/8411 NIC automatically uses the built-in r8169 but it is not a good match and can cause a number of seemingly unrelated issues. Can I suggest to update to the r8168 driver? You'll need to do:
yum install kmod-r816*Responses (6)
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Accepted Answer
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Accepted Answer
It seems like the problem has been solved.
I decided to not only switch off the router and the client machines, but also disconnect the Ethernet cables. That seems to have worked.
My analysis is, that powering off a client while keeping the network cable in place may leave enough current from the router network card to keep the memory of the client card active. If you subsequently power off the router, it will preserve the latest config info from the client card's memory. Thus, after restarting the router it will use the old memory.
I don't know whether this makes enough sense to explain my problem, but the problem seems to be over now. Thanks again for the help. -- Roel -
Accepted Answer
Thanks for helping me out, Nick. Here are the results. Roel
[roel@client ~]# cat /etc/resolv.conf
# Please do not edit this file.
# See http://www.clearcenter.com/support/documentation/clearos_guides/dns_and_resolver
domain domain.dom
nameserver 127.0.0.1
[roel@client ~]# cat /etc/resolv-peerdns.conf
; generated by /usr/sbin/dhclient-script
search domain.dom
nameserver 213.75.63.75 # DNS-server of my ISP
nameserver 213.75.63.76 # Originally I used the gateway at 192.168.2.254 and Google 8.8.8.8
[roel@client ~]# cat /etc/clearos/network.conf
# Network mode
MODE="standalone"
# Network interface roles
EXTIF="enp1s0"
LANIF=""
DMZIF=""
HOTIF=""
# Domain and Internet Hostname
DEFAULT_DOMAIN="domain.dom"
INTERNET_HOSTNAME="client.domain.dom"
# Extra LANS
EXTRALANS=""
# ISP Maximum Speeds
ENP1S0_MAX_DOWNSTREAM=0
ENP1S0_MAX_UPSTREAM=0
ENP0S20U1U4_MAX_DOWNSTREAM=0
ENP0S20U1U4_MAX_UPSTREAM=0
ENP0S20U1_MAX_DOWNSTREAM=0
ENP0S20U1_MAX_UPSTREAM=0
[roel@client ~]# cat /etc/sysconfig/network-scripts/ifcfg-e*
DEVICE=enp1s0
TYPE="Ethernet"
ONBOOT="yes"
USERCTL="no"
BOOTPROTO="dhcp"
PEERDNS="yes"
[roel@client ~]# ifconfig
enp1s0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.2.111 netmask 255.255.255.0 broadcast 192.168.2.255
inet6 fe80::2e0:4cff:feef:8380 prefixlen 64 scopeid 0x20<link>
ether 00:e0:4c:ef:83:80 txqueuelen 1000 (Ethernet)
RX packets 603881399 bytes 863812839880 (804.4 GiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 102634641 bytes 43147853556 (40.1 GiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
inet 127.0.0.1 netmask 255.0.0.0
inet6 ::1 prefixlen 128 scopeid 0x10<host>
loop txqueuelen 1000 (Local Loopback)
RX packets 3116883 bytes 2803572849 (2.6 GiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 3116883 bytes 2803572849 (2.6 GiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
tun0: flags=4305<UP,POINTOPOINT,RUNNING,NOARP,MULTICAST> mtu 1500
inet 10.8.0.1 netmask 255.255.255.255 destination 10.8.0.2
inet6 fe80::14a6:9c63:b73a:4c57 prefixlen 64 scopeid 0x20<link>
unspec 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00 txqueuelen 100 (UNSPEC)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 8 bytes 450 (450.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
tun1: flags=4305<UP,POINTOPOINT,RUNNING,NOARP,MULTICAST> mtu 1500
inet 10.8.10.1 netmask 255.255.255.255 destination 10.8.10.2
inet6 fe80::635d:5a4d:141d:5b66 prefixlen 64 scopeid 0x20<link>
unspec 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00 txqueuelen 100 (UNSPEC)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 8 bytes 450 (450.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
[roel@client ~]# lspci -k | grep Eth -A 3cat /etc/resolv.conf
grep: 3cat: invalid argument for context length
[roel@client ~]# cat /etc/resolv-peerdns.conf
; generated by /usr/sbin/dhclient-script
search domain.dom
nameserver 213.75.63.75
nameserver 213.75.63.76
[roel@client ~]# cat /etc/clearos/network.conf
# Network mode
MODE="standalone"
# Network interface roles
EXTIF="enp1s0"
LANIF=""
DMZIF=""
HOTIF=""
# Domain and Internet Hostname
DEFAULT_DOMAIN="domain.dom"
INTERNET_HOSTNAME="client.domain.dom"
# Extra LANS
EXTRALANS=""
# ISP Maximum Speeds
ENP1S0_MAX_DOWNSTREAM=0
ENP1S0_MAX_UPSTREAM=0
ENP0S20U1U4_MAX_DOWNSTREAM=0
ENP0S20U1U4_MAX_UPSTREAM=0
ENP0S20U1_MAX_DOWNSTREAM=0
ENP0S20U1_MAX_UPSTREAM=0
[roel@client ~]# cat /etc/sysconfig/network-scripts/ifcfg-e*
DEVICE=enp1s0
TYPE="Ethernet"
ONBOOT="yes"
USERCTL="no"
BOOTPROTO="dhcp"
PEERDNS="yes"
[roel@client ~]# ifconfig
enp1s0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.2.111 netmask 255.255.255.0 broadcast 192.168.2.255
inet6 fe80::2e0:4cff:feef:8380 prefixlen 64 scopeid 0x20<link>
ether 00:e0:4c:ef:83:80 txqueuelen 1000 (Ethernet)
RX packets 603895790 bytes 863833415052 (804.5 GiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 102636157 bytes 43147968361 (40.1 GiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
inet 127.0.0.1 netmask 255.0.0.0
inet6 ::1 prefixlen 128 scopeid 0x10<host>
loop txqueuelen 1000 (Local Loopback)
RX packets 3116903 bytes 2803577440 (2.6 GiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 3116903 bytes 2803577440 (2.6 GiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
tun0: flags=4305<UP,POINTOPOINT,RUNNING,NOARP,MULTICAST> mtu 1500
inet 10.8.0.1 netmask 255.255.255.255 destination 10.8.0.2
inet6 fe80::14a6:9c63:b73a:4c57 prefixlen 64 scopeid 0x20<link>
unspec 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00 txqueuelen 100 (UNSPEC)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 8 bytes 450 (450.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
tun1: flags=4305<UP,POINTOPOINT,RUNNING,NOARP,MULTICAST> mtu 1500
inet 10.8.10.1 netmask 255.255.255.255 destination 10.8.10.2
inet6 fe80::635d:5a4d:141d:5b66 prefixlen 64 scopeid 0x20<link>
unspec 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00 txqueuelen 100 (UNSPEC)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 8 bytes 450 (450.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
[roel@client ~]# lspci -k | grep Eth -A 3
01:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller (rev 07)
Subsystem: Realtek Semiconductor Co., Ltd. Device 0123
Kernel driver in use: r8169
Kernel modules: r8169
[roel@client ~]#
==================================
[roel@client ~]# cat /etc/resolv.conf
# Please do not edit this file.
# See http://www.clearcenter.com/support/documentation/clearos_guides/dns_and_resolver
domain domain.dom
nameserver 127.0.0.1
[roel@client ~]# cat /etc/resolv-peerdns.conf
; generated by /usr/sbin/dhclient-script
search domain.dom
nameserver 213.75.63.75
nameserver 213.75.63.76
[roel@client ~]# cat /etc/clearos/network.conf
# Network mode
MODE="standalone"
# Network interface roles
EXTIF="enp1s0"
LANIF=""
DMZIF=""
HOTIF=""
# Domain and Internet Hostname
DEFAULT_DOMAIN="domain.dom"
INTERNET_HOSTNAME="client.domain.dom"
# Extra LANS
EXTRALANS=""
# ISP Maximum Speeds
ENP1S0_MAX_DOWNSTREAM=0
ENP1S0_MAX_UPSTREAM=0
ENP0S20U1U4_MAX_DOWNSTREAM=0
ENP0S20U1U4_MAX_UPSTREAM=0
ENP0S20U1_MAX_DOWNSTREAM=0
ENP0S20U1_MAX_UPSTREAM=0
[roel@client ~]# cat /etc/sysconfig/network-scripts/ifcfg-e*
DEVICE=enp1s0
TYPE="Ethernet"
ONBOOT="yes"
USERCTL="no"
BOOTPROTO="static"
IPADDR="192.168.2.1"
NETMASK="255.255.255.0"
GATEWAY="192.168.2.254"
[roel@client ~]# ifconfig
enp1s0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.2.1 netmask 255.255.255.0 broadcast 192.168.2.255
inet6 fe80::2e0:4cff:feef:8380 prefixlen 64 scopeid 0x20<link>
ether 00:e0:4c:ef:83:80 txqueuelen 1000 (Ethernet)
RX packets 630472015 bytes 901857475631 (839.9 GiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 105631902 bytes 43364935226 (40.3 GiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
inet 127.0.0.1 netmask 255.0.0.0
inet6 ::1 prefixlen 128 scopeid 0x10<host>
loop txqueuelen 1000 (Local Loopback)
RX packets 3388298 bytes 3009859531 (2.8 GiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 3388298 bytes 3009859531 (2.8 GiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
tun0: flags=4305<UP,POINTOPOINT,RUNNING,NOARP,MULTICAST> mtu 1500
inet 10.8.0.1 netmask 255.255.255.255 destination 10.8.0.2
inet6 fe80::14a6:9c63:b73a:4c57 prefixlen 64 scopeid 0x20<link>
unspec 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00 txqueuelen 100 (UNSPEC)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 8 bytes 450 (450.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
tun1: flags=4305<UP,POINTOPOINT,RUNNING,NOARP,MULTICAST> mtu 1500
inet 10.8.10.1 netmask 255.255.255.255 destination 10.8.10.2
inet6 fe80::635d:5a4d:141d:5b66 prefixlen 64 scopeid 0x20<link>
unspec 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00 txqueuelen 100 (UNSPEC)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 8 bytes 450 (450.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
[roel@client ~]#
=================
The lspci -k command failed. I include the relevant part:
01:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller (rev 07)
Subsystem: Realtek Semiconductor Co., Ltd. Device 0123
Kernel driver in use: r8169
Kernel modules: r8169
02:00.0 Network controller: Realtek Semiconductor Co., Ltd. RTL8188EE Wireless Network Adapter (rev 01)
Subsystem: AzureWave Device 1d38
Kernel driver in use: rtl8188ee
Kernel modules: rtl8188ee
The Wireless Network Adapter is not in use. -
Accepted Answer
On one machine, please give the following:
Then change to static and give:cat /etc/resolv.conf
cat /etc/resolv-peerdns.conf
cat /etc/clearos/network.conf
cat /etc/sysconfig/network-scripts/ifcfg-e*
ifconfig
lspci -k | grep Eth -A 3cat /etc/resolv.conf
cat /etc/resolv-peerdns.conf
cat /etc/clearos/network.conf
cat /etc/sysconfig/network-scripts/ifcfg-e*
ifconfig -
Accepted Answer
Thank you, Nick. The short answer is: none of that. I use my ISP router as my gateway and DNS provider. The old router and the new one were both issued identical configs. My Windows computers don't notice any difference, but the ClearOS systems do. By the way, all ClearOS systems are running standalone nowadays.
I wrongly reported another problem, though.My new ISP router will issue fixed IP addresses but in order to do that, you need to fully power off the router and the clients. I had done reboots without power off. That obviously isn't sufficient (and I should have remembered that).
So I can solve my practical problem now, but still it doesn't make sense to me why ClearOS / the network cards cannot properly connect a fixed IP-address to a DNS configuration that seems to be OK. -
Accepted Answer
What DNS servers were your ClearOS boxes configured to use? Were they your old ISP's servers, by any chance? That generally does not work as many (but all) ISP's only allow connections from their own network. Or were they configured to use you old router's LAN IP and your new router is on a different LAN IP or subnet?
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