I have an issue with a linux Server that is unreachable on my network. I tried to plug the cable directly into my computer and ping the Server but I am unable to reach it. On top of that the ntmui command on Linux does not work. I used the same cable that I plugged on my computer and to the same switch and I was able to have access to the network. What else should I check on the server?
unable to ping network address on linux server
- Thread starter ekemini87
- Start date
MattWinter
Active Member
I'm not sure what you're saying, but if you're saying you plugged two computers together with a CAT 5 cable, that won't work.
You either need to use a crossover cable, or you need to plug both computers in to a switch or a hub or a router.
You either need to use a crossover cable, or you need to plug both computers in to a switch or a hub or a router.
I was typing the same when @MattWinter's message appeared. Allow me to add:
Both the Linux Server and the computer must be manually configured to be on the same network segment unless there is a router. In addition, if either of them relies on DHCP for network configuration (IP address, netmask, gateway), then a DHCP server must also be on the network.
These days, many systems have auto-configured Ethernet ports that eliminate the need for a crossover Ethernet cable. Older systems may still require one.
Here is another idea: Connect a keyboard and monitor to the server.
Does the server have interfaces for a keyboard and monitor? You may be able to login through the console. Are there available ports on the physical server? Can you use them?
Does the server have interfaces for a keyboard and monitor? You may be able to login through the console. Are there available ports on the physical server? Can you use them?
MattWinter
Active Member
Oh! I didn't know this.
Yeah. Macs have done it for many years, and probably most other brands of equipment. I take it for granted these days and just cable 'em together. To be honest, I lost track of which is the crossover cable. (If I need an Ethernet crossover cable, I have the tooling to make another one.)
Assuming that you are wanting the server connected on your local network which is the same network your desktop is connected to through your switch and that your router is doing dhcp for your local network. Then my first guess would be that your desktop system has dhcp configured and your server doesn't. The first thing to do would be to login into your server and check the network configuration and compare it to that of your desktop system. Is the ip address in the correct range, are the sub-net mask and gateway the same? The other option would be just to enable dhcp on your server's network interface and have a static ip address assigned through your router's dhcp service based on the mac adress of your server's network interface.
permit me to rephrase my question, I have a centOS 7 installed on an HP Proliant machine, with one port to sniff network packets connected to a nexus switch and another to the management port connected to a server vlan switch that is suddenly unreachable on my network, when I use the ( cat /etc/sysconfig/network-scripts/ifcfg-<interface> ) command it displays the right information assigned to the interface
but I CANT reach the assigned IP remotely or ping the GATEWAY.
To isolate the issue I connected my laptop via LAN to the Centos 7 server assigned an IP range with the server, still can't ping the GATEWAY
the second step of isolation is I connected my laptop to the port on the server vlan switch, and I could ping the gateway successfully.
but then I still can't ping the IP address assigned to the centos machine, neither can I ping the gateway from the cli of the machine, also I have noticed the (ntmui) command does not work either
but I CANT reach the assigned IP remotely or ping the GATEWAY.
To isolate the issue I connected my laptop via LAN to the Centos 7 server assigned an IP range with the server, still can't ping the GATEWAY
the second step of isolation is I connected my laptop to the port on the server vlan switch, and I could ping the gateway successfully.
but then I still can't ping the IP address assigned to the centos machine, neither can I ping the gateway from the cli of the machine, also I have noticed the (ntmui) command does not work either
permit me to rephrase my question, I have a centOS 7 installed on an HP Proliant machine, with one port to sniff network packets connected to a nexus switch and another to the management port connected to a server vlan switch that is suddenly unreachable on my network, when I use the ( cat /etc/sysconfig/network-scripts/ifcfg-<interface> ) command it displays the right information assigned to the interface
but I CANT reach the assigned IP remotely or ping the GATEWAY.
To isolate the issue I connected my laptop via LAN to the Centos 7 server assigned an IP range with the server, still can't ping the GATEWAY
the second step of isolation is I connected my laptop to the port on the server vlan switch, and I could ping the gateway successfully.
but then I still can't ping the IP address assigned to the centos machine, neither can I ping the gateway from the cli of the machine, also I have noticed the (ntmui) command does not work either
any help?
permit me to rephrase my question, i have a centOS 7 installed on a HP Proliant machine, with one port to sniff network packets connected to a nexus switch and another to management port connected to a server vlan switch that is suddenly unreachable on my network, when i use the ( cat /etc/sysconfig/network-script/ifcfg-<interface> ) command it displays the right information assigned to the interface
but i CANT reach the assigned IP remotely or ping the GATEWAY.
To isolate the issue i connected my laptop via LAN to the centos 7 server assigned an ip range with the server , still cant ping the GATEWAY
second step of isolation is i connected my laptop to the port on the server vlan switch , and i could ping the gateway successfully.
but then i still cant ping the ip address assigned to the centos machine, neither can i ping the gateway from the cli of the machine, also i have noticed the (ntmui) command does not work either
its a static and not a dhcp.
permit me to rephrase my question, i have a centOS 7 installed on a HP Proliant machine, with one port to sniff network packets connected to a nexus switch and another to management port connected to a server vlan switch that is suddenly unreachable on my network, when i use the ( cat /etc/sysconfig/network-script/ifcfg-<interface> ) command it displays the right information assigned to the interface
but i CANT reach the assigned IP remotely or ping the GATEWAY.
To isolate the issue i connected my laptop via LAN to the centos 7 server assigned an ip range with the server , still cant ping the GATEWAY
second step of isolation is i connected my laptop to the port on the server vlan switch , and i could ping the gateway successfully.
but then i still cant ping the ip address assigned to the centos machine, neither can i ping the gateway from the cli of the machine, also i have noticed the (ntmui) command does not work either
Where to begin...
If you're using network-manager ( nmtui for example ) you can't depend on the /network-scripts/ifcfg-<interface> files.
Try this...
nmcli con show
This will list all your connection names in network-mananger
Then do a ...
nmcli con show < connection name >
you can also use
ip addr
to see the IP assigned to the interface.
and you can use
ip route
or netstat -nr
to see your default gateway.
Can you ping yourself locally at that IP address. ( this will test the interface )
don't use localhost, use the assigned IP address.
If neither your laptop nor the server can reach the gateway through your switch...
then likely the nexus switch is bad. It could be your NIC or it could be a bad cable,
but it's pretty unlikely they would be bad on both computers.
If you by-pass the switch and see the gateway, it seems that would confirm your
switch is bad. Can you try another port on the switch?
If you're using network-manager ( nmtui for example ) you can't depend on the /network-scripts/ifcfg-<interface> files.
Try this...
nmcli con show
This will list all your connection names in network-mananger
Then do a ...
nmcli con show < connection name >
you can also use
ip addr
to see the IP assigned to the interface.
and you can use
ip route
or netstat -nr
to see your default gateway.
Can you ping yourself locally at that IP address. ( this will test the interface )
don't use localhost, use the assigned IP address.
If neither your laptop nor the server can reach the gateway through your switch...
then likely the nexus switch is bad. It could be your NIC or it could be a bad cable,
but it's pretty unlikely they would be bad on both computers.
If you by-pass the switch and see the gateway, it seems that would confirm your
switch is bad. Can you try another port on the switch?
Here it sounds like the port where your laptop is connected to a utp port that isn't connected to a switch containing the vlan your server is connected to and your tried to assigned an ip from the vlan your server is connected. So it's pretty logical that you are not able to ping the gateway in this case.
If I remember correctly if you are connected to the same vlan as another system and in the same switch you don't need to be able to reach the gateway in order to contact the other system since you are in the same network. Your laptop being able to ping the gateway here means that your laptop should be able to reach other systems outside of the network it is located in.
It's quite strange that you can't reach the server while your laptop is connected in the same vlan in that situation. It makes it seems to me be that the port in the management vlan that the server is connected to isn't configured correctly or doesn't have link.
What happens when you run the following command on the centos7 server?
Code:
ethtool eth0
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So the switch port the server was connected to was not configured correctly?
@ekemini87
There's no need to repeat the same thing to multiple users as replies to their comments. You can just say it once and add usernames as I did with your username in this post. Otherwise, it's pretty spammy. Thanks for cooperating.
There's no need to repeat the same thing to multiple users as replies to their comments. You can just say it once and add usernames as I did with your username in this post. Otherwise, it's pretty spammy. Thanks for cooperating.
