I have been learning some network and system administration and encountered a puzzling problem.
SETUP:
I setup a small local offline network with a Windows Server 2019 and a Ubuntu server hosting gitea. In the Windows Server I have assigned a static IP of 169.254.0.2 and installed DNS and DHCP roles. In the Ubuntu server I have assigned a static IP of 169.254.0.3.
DNS has been configured with a primary zone funlab.abc. I created a single A record for gitea.funlab.abc. to point to 169.254.0.3. DHCP has been configured to lease addresses from 169.254.0.100 to 169.254.255.254. Subnet mask is 255.255.0.0.
PROBLEM:
With this setup, I successfully got client machines to connect to the local LAN network, transparently get a dynamic IP address, and access gitea.funlab.abc through the browser.
But in windows 10 client machines, I am unable to run ping gitea.funlab.abc in command prompt. I get an error message :
Ping request could not find host gitea.funlab.abc. Please check the name and try again
Git clone/push operations involving the URL gitea.funlab.abc also does not work.
However I can run ping -4 gitea.funlab.abc successfully. Git clone/push operations can also work if I replace the URL with the static IP. nslookup gitea.funlab.abc works correctly as well.
QUESTION:
Why is this happening? What did I misconfigure such that ping and git commands do not work?
Turns out ping and git commands works just fine when I change the IP address to 192.168.X.X. I guess windows treat the 169.254.X.X addresses differently.
Related
I have installed Virtual Box (Version 5.2.0 r118431 (Qt5.6.2)) on Windows 10 and i imported appliance HDP_2.4_virtualbox_v3 (downloaded from here).
I followed the tutorial from here step by step.
The virtual machine is running on the computer from where I am trying to access the Dashboard. I have set up the Host Only Adapter Option on the sandbox so the computer and the virtual machine can communicate
After the CentOs finished booting I am prompt to enter to the ip 127.0.0.1:8888, which is a different address from the tutorial,
and there is no server listening to that address because i get
"127.0.0.1 refused to connect." in the browser.
image here
Run the ipconfig command in your command prompt and identyfy your virtual box's ip under Ethernet adapter VirtualBox Host-Only Network.
Take that ip address and go to your Virtual Box.
Select your appliance and go to Settings->Network->Adapter 1->Port Forwarding.
Replace the Host IP 127.0.0.1 for the port you need 8080, 8888 and so on with the ip of your virtual box that should be sth like 192.168.x.x.
Now start your sandbox, login on it and try to connect in your browser to the new ip set 192.168.x.x:8888.
Use appliance HDP_2.4_virtualbox because in the most recent some linux commands like netstat are considered deprecated and no longer function, which willmake your life harder when trying to debug or identify a networking problem.
If you still encounter issues eith it, reinstall your operating system, reinstall your virtual box and reimport the sandbox, make the changes needed in the Port Forwarding settings and it should be ok.
try to connect using 127.0.0.1 to connect make sure the VM is running make sure there are no errors if there are debug them and at the last straw uninstall the Vm and retry (make sure to make a backup if there are any files)
you can also try to check all the local host ips on your network and try to connect to them
Make sure you set NAT in your VirtualBox network settings:
I am in the process of setting up a Hadoop cluster of virtual machines on my LAN and a process on one of the vms (the ResourceManager) provides a Web UI which is exhibiting strange behavior. All vms run from my desktop and have been assigned ips.
The URL I am targeting is resourcemanager:8088 and here is the behavior.
From other vms running on my desktop:
curl -v resourcemanager:8088
returns an HTTP 302 Found response with Location: http://resourcemanager:8088/cluster. Looking this up I saw this is a redirect, and curl -L resourcemanager:8088 successfully retrieves the HTML.
From the desktop running the vms:
Trying to reach the URL from (Chrome) browser gives net::ERR_CONNECTION_REFUSED. Also
curl resourcemanager:8088
returns curl: (7) Failed to connect to resourcemanager port 8088: Connection refused.
Each vm has the same /etc/hosts:
::1 localhost
127.0.0.1 localhost
10.0.0.3 namenode
10.0.0.4 resourcemanager
10.0.0.5 datanode1
and the .../drivers/etc/hosts file on my (Windows) desktop looks the same minus the localhost lines.
To make matters more complicated, a second process (the NameNode) also provides a web ui, call it namenode:50070, and I am able to curl it from both the desktop and vms, and I can get to it via browser from my desktop.
Any ideas?
EDIT
Specs:
Desktop OS: Windows 10
VMs OS: Arch Linux latest (Linux kernel 4.5.4)
An initial Arch+hadoop VM was created with Hyper-V, then cloned to create the three "cluster" vms listed above. After cloning, each vm was given a unique hostname (listed above) and assigned a reserved IP address from my router (also listed above). All VMs use an "external vm switch".
I cannot comment, because I do not have 50 reputation yet, but that might have to do with the configuration of the service behind port 8088: The VM probably got a 'small' netmask from the virtual dhcp server, which presumably covered the IP range of all other VMs, not including the host machine. If that had happened and the service was configured like many others -to listen on all interfaces- it would not react on requests and your connection would reach a closed port, causing a 'connection refused' error. How is that?
I'm trying to copy my public key from a CentOS environment to a Ubuntu machine. I used the following command
ssh-copy-id root#Ubuntu_IP
However I get an error saying Connection timed out. I'm able to ping from my host to the remote machine. The purpose behind this is that my host machine is ansible control node where as Ubuntu machine is my managed node.
Make sure you add a permanent route in the remote machine for the host machine.
route add -net remote_ip netmask mask_ip gw gateway_ip eth0
Also disable the firewall on the remote machine. This seemed to have solved the problem in my case.
I am trying to run putty on Windows 7.
I need to run some SSH commands to upgrade Magento. Every time putty gives me this fatal error:
network error: connection refused
I have even tried to use it through winSCP. Note that putty is running fine on my client's side, but for me it's giving me that error every time.
I tried using port 22, 23 and a few others without success. I have also tried with Windows Firewall both enabled and disabled.
Thank you.
Install open-ssh or ssh in target Linux machine solved my problem .
Use below commands:
sudo apt install ssh
sudo systemctl status ssh
sudo systemctl enable ssh
The following are the list of possibilities of this error:
1) Common cause is - Your IP is blocked or not whitelisted in the server which can be done by editing the file at /etc/csf/csf.conf
2) Disable the windows firewall settings and check..
The above two things should work in most of the cases
3) This is very unusual and when the above two options fails it is very difficult to find the solution
In this case the traceroute to the server host or IP works usually but putty fails
port 22 looks normal and working but connection fails and restarting SSH (service ssh restart) also does not work
reboot or restart the server but still fails
Adding IP in firewalls or whitelisting the local IP may not workout
This case generally happens when the server is migrated or new server. IP of the old server might be whitelisted locally, but don't have port 22 open, or some other local filtering is occurring for this new IP but not the old server IP..
In this case you need to change the port to some 522 or 530 some unusual port will help in sorting it out.. The same port you have to use for the SFTP connection also .. where as FTP connections works normally..
or you have to whitelist the IP locally or open the TCP in and out to port 22 if you want to use the port 22..
I am using ubuntu 11.10 and have installed different virtual host on different ip like
127.0.0.2 www.example.local
127.0.0.3 www.wordpress.local
... etc
I want to test these website in IE9, for this i have install windows7 in oracle virtual box and also modified host file of windows7 and add this line 10.0.2.2 localhost at the end of the file and also create a new bridge adapted.
After all this setup i can access localhost of ubuntu from windows7, but find problem while accessing virtual host of ubuntu.
Please help me to access these virtual host on windows 7, i have already search google, ubuntu forum and stackoverflow for this but didnt find right answer.
If I understand you correctly, you want the virtual adapters ip, ie. the gateway ip.
Just add those lines you have added to Ubuntu's host file to the host file in your Windows 7 VM, replacing 127.0.0.x with 10.0.2.2 should make your Windows VM connect to your Ubuntu host for requests to those hosts. This should usually sufficient, unless your HTTP server is configured to serve www.example.local only for connection to 127.0.0.2 and similar for www.wordpress.local.