Networking

A basic understanding of networking is important for anyone managing a server. Not only is it essential for getting your services online and running smoothly, it also gives you the insight needed to diagnose problems.

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823 Results
  • Question

    How to ping Docker container from another container by name?

    Hi all, I want to be able to ping or basically access a running docker container from another container by simply using the docker name rather than an IP address. I've tried a few guides but I could not get it working...
    Accepted Answer: Hello, Yes this now comes more or less out of the box with Docker Networks, so what you need to do is: Create two containers: docker run -d --name <^>web1<^> -p 8001:80 eboraas/apache-php docker run -d --name <^>web...
    1 By devdojo Docker Linux Basics Networking Ubuntu
  • Question

    Cannot connect to Postfix on port 587

    Hi there, I have installed Postfix on a droplet, and configured it to work on ports 25 and 587. I'm unable to make a connection remotely. If I do the following from the droplet itself: ``` telnet localhost 587 ``` I g...
    Accepted Answer: Hello, This sounds like that you might have a firewall on your Droplet. If this is the case you need to open port 587 for incoming and outgoing TCP connections, for example if you are using Ubuntu and if you have UFW ...
    1 By DigitalCarrot Networking
  • Question

    Private IP is not created for custom image

    I am using the API to spin up a droplet that uses a custom image. I have enabled private ip at the time of creation but no network is created in the droplet. I can see in the DigitalOcean control panel that private ne...
    Accepted Answer: The device itself is properly created ( ens4 ) so the missing piece is likely the integration of the metadata with the interface configuration. This is generally done with cloud-init, which should be aware of using th...
    1 By zboyet Custom Images Networking
  • Question

    Can Cilium Network Policy be leveraged to blacklist troublesome hosts

    I have been developing a web app living in DO's managed Kubernetes, and am researching the best way to blacklist Internet ingressed hosts that are an issue. For example, I flag a host as attempting bad authentication ...
    Accepted Answer: hi there, You could certainly use networkPolicy objects to enforce rules like you described. Another option would be to use a single LB for an ingress controller and then police the traffic at that point. For example ...
    1 By pinion Kubernetes Networking
  • Question

    How to solve clusterissuer challenge timeouts?

    Setup: DO K8S Cluster w/ 2 nodes and 1 Ingress-NGINX LoadBalancer I was wondering why certificate requests fail and found in the logs of the Challenge, that the self check GET request runs into timeout. After looking ...
    Accepted Answer: Posted the same issue on SO, and already got an answer there: https://stackoverflow.com/questions/59286126/kubernetes-cluterissuer-challenge-timeouts For me, this is an acceptable workaround for now. Hope this can hel...
    2 By thc Kubernetes Nginx Load Balancing Networking DigitalOcean Managed Kubernetes
  • Question

    IP address worked but domain name does not

    Domain name is registered and DNS is pointed to DO as per tutorial. Created "A" record for fireball.design and www.fireball.design and *.fireball.design. Also created Nginx server block for fireball.design in /etc/ngi...
    Accepted Answer: Tried the Fail2ban stuff but nothing worked and even uninstalled it. Tried lots of other things. I give up 3 weeks later for a simple LEMP stack with Wordpress. One click garbage installs. Can somebody delete this wh...
    3 By AndreyPavlov DNS Initial Server Setup LEMP Networking Nginx PHP WordPress Ubuntu 18.04
  • Question

    Some traffic does not reach our site

    Hi! We have been experiencing some weird behaviour on our site that is hosted on our droplet (currently only one). Currently we have a check on pingdom that checks the uptime of some of our services, this check has be...
    Accepted Answer: This issue has been resolved. It was a compability issue between the mpm and http2 module in apache. This resulted in random segfault errors.
    2 By viktorwml CentOS Apache Networking
  • Question

    Redirect one domain to a subfolder inside another domain

    Hi, I have product.com and company.com I would love to figure out how to tell both the DNS and Nginx to redirect product.com to a folder inside the company.com domain. Ideally all these permutations http://product.co...
    Accepted Answer: Hi @digitaldev, Using DNS for a HTTP redirection is not possible with just DNS. There are companies providing DNS forwarding though. As for the Nginx rules, now that's possible. You can server_name which supports s...
    1 By digitaldev Nginx Networking
  • Question

    How to direct domain bought at Wix to my droplet without using nameservers?

    Hi everyone, I've done a small mistake by buying a domain on Wix as they don't allow changing nameservers. How can I go about using my domain on my droplet here using CNAME or A records which they allow to edit? Or sh...
    Accepted Answer: Hello, You need to point the A record of your domain name to the IP address of your server/droplet, make sure to do this for the www version of your domain name as well, or just make sure that you have a CNAME for the...
    1 By maxwellcooperman Networking
  • Question

    Monitoring DO network stability

    Every once in a while either due to unforeseen networking issues or due to DO maintenance I forgot to schedule in Nagios, I get an alert blast due to so many connectivity issues timing out. Is there a good endpoint to...
    Accepted Answer: I think you should be able to accomplish that by running a ping check against the network gateway that is set on the droplet. While you could monitor a higher level "network" abstraction, it wouldn't necessarily solve...
    1 By VxJasonxV Monitoring Networking
  • Question

    Droplet No Network After Resize, Can't Ping or SSH

    I have a DO droplet running and after resizing I can't connect to the internet..I emailed them but they are taking days to respond. At first the interface changed from eth0 to ens3 and I managed to change it back: ifc...
    Accepted Answer: I fixed this by the comments here: https://unix.stackexchange.com/questions/538907/ubuntu-18-network-is-unreachable-cant-ping-dns
    1 By usgoose Networking Ubuntu 18.04
  • Question

    Networking not working after droplet resize

    Hello Everyone, I resized my droplet yesterday and the process went through without any errors or warnings. When I powered on, I discovered that my networking had stopped working. I'm able to access it through the web...
    Accepted Answer: So I managed to fix the issue. Turns out my both interfaces eth0 and eth1 are going down after a reboot. I have to run the following after that: ip link set eth0 up ip link set eth1 up ip addr flush dev eth0 ip addr ...
    3 By sachinmehta Networking Ubuntu 18.04
  • Question

    adding subdomain in apache virtual host

    I am trying to configure a subdomain: api.example.com (exapmle.com is replaced by my actual domain name) I already had virtual hosts set up with 2 sites: example.com and example.nl they both had separate directories a...
    Accepted Answer: @jop02 You are redirecting the traffic from http://api.example.com to https://api.example.com so you need to setup another virtual host for https://api.example.com where it listen on port 443 and uses a certificate f...
    1 By jop02 Apache DigitalOcean Networking Ubuntu Ubuntu 18.04
  • Question

    How to setup ssl (HTTPS) on 1-click install Gitea droplet?

    I have a 1-click install droplet with Gitea, but it only works over HTTP how can I set it up to work over HTTPS?
    Accepted Answer: I have figured out how to set it up (but I think it only works with domain names though...) And don't use the 1-click droplet, instead create a standard ubuntu 18.04 droplet : Initial updates & installs apt-get updat...
    3 By Buscedv DigitalOcean Git Networking Let's Encrypt Ubuntu 18.04
  • Question

    No internet/connection after droplet reboot

    After rebooting Ubuntu 18.04 Droplet I couldn't access it via SSH. Then I realized that I don't receive any response when pinging its IP. I connected to my Droplet through DigitalOcean built-in terminal and tried to p...
    Accepted Answer: After almost two weeks since I raised this issue, I was finally able to resolve it. The problem occurred in the first place because different packages got uninstalled somehow when I rebooted. This includes cloud-init,...
    5 By lukasea17033bb7e7ecf80fc21 Networking Ubuntu 18.04
  • Question

    Cannot ping newly created droplet, but ssh and browsing to the IP address work. Firewall is disabled

    Hi All, I have the same issue described here https://www.digitalocean.com/community/questions/scp-fails-while-ssh-works Any suggestions? The droplet was created using the LAMP image from the marketplace, and UFW is di...
    Accepted Answer: Hello, I tried recreating this at my end and indeed once you deploy the LAMP image from the marketplace you can not ping it. But once I've disabled the UFW I was able to ping it. Can you run the following commands and...
    1 By mirkomen77 Networking Ubuntu 18.04
  • Question

    Outgoing Port 25 is blocked, How can I enable it?

    I have tried everything but Outgoing Port 25 still disable or Deny, Can you please reply me on my support Ticket #479378, Really your support is terrible and you wast lots of my time :( *``` root@iMaker-test:~# telnet...
    Accepted Answer: My issue has been solved by Digitalocean support team, Thank you all Who tried to solve my issue...
    5 By iMaker Networking Email Ubuntu 16.04
  • Question

    ssh-copy-id from old VPS (ec2) to new droplet gives Permission denied (publickey) error

    Hello, I am trying to migrate my web application from my old vps (amazon EC2) to my new droplet, following this DO guide (https://www.digitalocean.com/community/tutorials/migrate-your-current-vps-linode-rackspace-aws-...
    Accepted Answer: I solved my problem by following the suggestions (https://www.digitalocean.com/community/tutorials/how-to-set-up-ssh-keys--2?comment=44107) of @LindsayBSC with a slight change. Here is what I did to solve the problem....
    3 By umbertofilippo Networking Initial Server Setup Ubuntu 18.04
  • Question

    Unable to reach DigitalOcean server from Russia

    I am unable to reach DigitalOcean droplet IP addresses from any local ISP in Russia. How do I fix this? (This question is part of a series in which we ask questions using language that is similar to common support tic...
    Accepted Answer: Greetings! I'm sorry to hear about the trouble this is causing for you. While we have heard several cases of ISPs in Russia blocking access to DigitalOcean IP addresses, it is not necessarily a universal truth that cu...
    6 By jarland Networking
  • Question

    Intermittent connection refused with cURL on localhost only

    After updating my droplet running Ubuntu 17.10 a week ago I have been experiencing intermittent "Connection refused" errors when making requests to my API using cURL. After spending hours narrowing down the cause of t...
    Accepted Answer: I'll answer my own question for anyone else having the same issue. After days of trying to figure out what the issue was, a Stack Overflow answer on an unrelated topic pointed me in the right direction. I knew that wh...
    2 By chrisjonesio Networking API Development DNS Ubuntu