This website provides documentation for administrators of 0th Root Secure Network — 0SNet. To know about the product, kindly visit our product website.

Getting Started

0th Root Secure Network — 0SNet works at the domain level and all subdomains of the chosen domain. For example, if you choose a domain example.com then 0SNet will secure all subdomains of example.com ie., *.example.com. Ideally, a third level domain is chosen, such as corp.example.com to secure *.corp.example.com.

1. Network Firewall

It is important that whichever host you setup 0SNet on, only that host has access to the protected servers and configured applications.

2. Email Address

An administrator email address need to be specified at the time of configuration. This is the email address which will receive the password protected certificate. Only by using the certificate, can 0SNet be accessed. However, 0SNet can be reconfigured, if there were any mistakes made.

3. Operating System

The server hosting 0SNet should be capable of running Apache HTTP server (2.4.3+). Currently, RHEL 7 and its derivatives are supported, such as CentOS 7.

If you're on AWS or GCP or Azure, you can use our public AMI or Custom Image or Azure Compute Gallery to launch a new instance, it comes with 0SNet pre-installed.


This section will help you through the process of installing 0SNet on your server. Please read Getting Started and have the domain information, administrator email, and the server details ready.

And, open ports 80 (HTTP) and 443 (HTTPS) on the server for 0SNet to work.


1. Platform setup

Run the following command and set SELinux to disabled,

sudo sed -i "s/^SELINUX=.*$/SELINUX=disabled/" /etc/selinux/config

Restart the server,

sudo systemctl reboot

Once the server is up, run the following commands to start 0SNet server on boot,

sudo chmod +x /etc/rc.d/rc.local
sudo bash -c 'echo "0snet --start" >> /etc/rc.d/rc.local'

2. Pre-requisites

Install Apache HTTP server, the SSL module and the required tools, as follows,

sudo yum install httpd mod_ssl wget bind-utils cronie lsof rsync

Ensure that default configuration of Apache HTTP server is not used,

sudo systemctl stop httpd.service
sudo systemctl disable httpd.service
sudo systemctl mask httpd.service

Open ports 80 and 443,

sudo firewall-cmd --permanent --zone=public --add-port=80/tcp
sudo firewall-cmd --permanent --zone=public --add-port=443/tcp
sudo firewall-cmd --reload

3. Installing 0SNet

To install the packages, 0snet and 0snet-uman, we need to directly use the rpm command instead of yum. This is because of the EULA that gets shown at the time of installation. Please run the following command to install 0SNet,

sudo rpm -Uvh https://www.0throot.com/download/x86_64/{0snet,0snet-uman}.el7.rpm

Public AMI

0SNet is available as a public amazon machine image (AMI) in N. Virginia, Mumbai and Singapore regions. If you require the AMI in any other region, we can make it available.1

In AWS console (see image below), choose the correct region,

  • Open services and select EC2
  • On the sidebar, select AMI under Images
  • Select Public Images in the drop down to the left of search bar
  • Search for keyword, 0snet
  • Choose 0th Root Secure Network and click Launch 2
  • Remember to open ports 80 and 443 when configuring Security Group

Once the instance is successfully created, add a wildcard DNS record for the chosen domain, such as *.corp.example.com, to its Elastic IP.

[1] You can also bear the minor costs and copy the AMI.
[2] To login to the new instance, SSH as ec2-user@Elastic-IP.

Custom Image

0SNet is available as a publicly shared custom image. gcloud CLI can be used to create a new instance from this custom image. The uri of the image family is listed below,


The following command1 creates a new instance from the custom image, with HTTP (80) and HTTPS (443) ports open,

gcloud compute instances create INSTANCENAME --image-family https://www.googleapis.com/compute/v1/projects/id-0snet/global/images/family/stable-0snet --tags http-server,https-server

On successful run of the above command, a new instance is created. Now, add a wildcard DNS record for the chosen domain, such as *.corp.example.com, to the displayed External IP.2

[1] choose zone and machine type with options --zone and --machine-type
[2] remember to make the external IP static

There are two approaches available to setup 0SNet in Azure, ie., by creating a virtual machine directly or through Azure Compute Gallery. At the moment, it is easier to directly create the virtual machine and do the installation.

Virtual Machine [RECOMMENDED]

Go to create Virtual Machine page and follow the steps below

  • Under BASICS Tab,
    • Choose New Resource Group eg:- snet
    • Choose Region
    • Choose Image "CentOS-based 7.9 Gen 1" (Search: centos)
    • Choose Instance Size (Minimum 1GB RAM, Recommended 4GB RAM)
    • Inbound Port Rules, Choose SSH, HTTP and HTTPS
  • Under NETWORKING Tab,
    • Choose Virtual Network (should be same as Application) [IMPORTANT]
  • Go to REVIEW + CREATE and create the virtual machine

Once the virtual machine is created, add a wildcard DNS record for the chosen domain, such as *.corp.example.com, to the server's Public IP. After which, login over SSH and follow the manual steps.

Azure Compute Gallery

0SNet is available as an image in azure compute gallery. To access the image across tenants, authorization is required. The steps below require access to azure CLI,

1. Create a new Resource Group

az group create --location <location> --name myVM_group

2. Identify your tenant ID

az account show --query "tenantId"

3. Open the following authorization URL, after substituting <tenantId>


4. Authorize access to the resource group (myVM_group), as shown in the images below,

5. To install from the image, run the commands listed below. Reach out to us at support@0throot.com to get <Your-Password> (expires in a few days)

az account clear
az login --service-principal -u "0f844e19-3145-4179-9c89-7b1b60901481" -p "<Your-Password>" --tenant 08480fa8-ba9f-4101-9723-366c81d85da4
az account get-access-token
az login --service-principal -u "0f844e19-3145-4179-9c89-7b1b60901481" -p "<Your-Password>" --tenant <tenantId> 
az account get-access-token
az vm create --resource-group myVM_group --name myVM --image "/subscriptions/64ad2f3a-04fd-497f-818b-db5793b0e828/resourceGroups/images/providers/Microsoft.Compute/galleries/0snet/images/stable/versions/latest" --admin-username azureuser --size Standard_B1s --ssh-key-name mykey --vnet-name myVM_vnet

6. Remove Authorization (IMPORTANT)

Once az vm create command executes succesfully, add a wildcard DNS record for the chosen domain, such as *.corp.example.com to the VM's public IP.

(The above method is NOT RECOMMENDED as it uses Contributer role)

0SNet is provided as per these terms of use and privacy policy .

If you face any problems, please feel free to contact us.


If you have chosen a domain such as .corp.example.com. You should configure your nameserver (DNS) to resolve the wildcard entry *.corp.example.com to the IP address of 0SNet server.

When Google Sign-In or Microsoft Sign-In is enabled, 0SNet will require login through the corresponding user account. Hence, don't use group email address or a mailing list during configuration.

If 0SNet is hosted on a server without public IP, change the Let's Encrypt mode to DNS with the command: sudo 0snet --letsencrypt mode dns

Setup (1/3)

Type the following command,

sudo 0snet --configure

This should bring up the following screen,

Fill out the form with your domain name, organization name, email ID and user ID. TLS certificate for the administrator will be sent to the specified email address. Choose your user ID carefully, because it will not be possible to modify this later.

IMPORTANT: Note down the password. In case you don't remember it, you can reconfigure 0SNet using,

sudo 0snet --configure

After the Setup Complete message, you should receive an email at the specified address, check your spam/bulk folder if necessary. The email should contain one attachment, sign.p12. It is your personal certificate encrypted using the password and it should be imported into your browser under personal certificates. If you are unsure, as to how to import the certificate, kindly follow the steps here.

Management Interface (2/3)

Once the certificate is imported, you will be able to access the management interface. A special subdomain 0snet is reserved for this purpose. For example, If you have configured your domain as .corp.example.com, you should open https://0snet.corp.example.com.

On successful connection, Browser will ask for a client certificate to be selected. On choosing the correct one, a login page for 0SNet will be shown. Enter the generated password, and change the password after successful login.

Hosts (3/3)

Host Manager should be used to add subdomains, along with IP address / Hostname of origin server, as shown in the image below,

After adding the subdomain, click on Validate Now to validate the domain. The new subdomain will be ready to use within 5 mins.


0SNet sends an email to users containing their personal certificate file. In this section, the steps to import the certificate has been provided in detail,

Windows Mac Linux / Firefox / Other

Android / iOS / Windows / Mac

On most devices, simply opening the sign.p12 file (double-click or tap to open) is sufficient to import the certificate.


On Linux / Firefox / Opera browser, Search for "certificates" in the browser settings or preferences, and you will likely find "Manage Certificates" or "View Certificates". On opening it, click the Import button under "Your Certificates" or "Personal Certificates" tab and choose the certificate file, sign.p12.

On Google Chrome, you can use the direct link chrome://settings/certificates.

When prompted for a password, type the generated password that has been provided by the administrator.

The certificate should be imported successfully.

To protect the imported certificates, it is recommended that you set a Master Password for the browser.

Application Access Controls

By default, all users have equal access to the subdomains, ie., *.corp.example.com. To differentiate users and grant access only to specific subdomain(s), ie., webapp.corp.example.com, access controls should be used. The link to access controls page can be found in user manager.

There are two distinct sections in access controls, ie., the Default and Groups sections.


The default behavior of access controls is governed by this section. There are three components that work together, ie., mode, statements and exceptions, as shown in the image below,

The Update statements button will be disabled until mode or statements has been changed. On successful update, the access controls are immediately applied. Hence, it is recommended to make all the changes at once.


The default mode can be one of two values, Allow (or) Deny. In Allow mode, as the name suggests, all incoming requests are allowed after successful authentication, while in Deny mode, they are rejected as unauthorized.


To alter the default behavior, along with the default mode, statements can be used. The syntax of a statement is as follows,

<deny or allow> <subdomain> [</url> or </urlprefix>]

All statements in the example below are valid, they collectively define access for users,

 allow myapp.corp.example.com
 deny myapp.corp.example.com /this/path/*
 deny webapp.corp.example.com /this/file.php

URL path prefix or an absolute path to file can be optionally specified, as shown in the example above. However, query string and anchor element cannot be matched.


To bypass default mode and statements, an exception can be added for specific users. An exception is an association of user to a specific mode. While an exception exists for the user, default mode and statements will not apply, and only the mode associated to the user will apply.


To specify access controls for a set of users, control groups can be used. Each group can have its own statements and users, as shown below,

Users can be part of multiple groups and control statements of all those groups will be used for authorization, along with default statements (if applicable). In case of conflicts, longer URL paths and deny statements take higher precedence.

NOTE: Admin user created at the time of 0SNet setup cannot be part of control groups.

To remove user from a control group, click on the user row and confirm. To quickly remove without any confirmation, hold CTRL key when clicking.


Details of last update can be checked with,

sudo 0snet --ac

0SNet versions update to mode and/or statements, above command will output details of current version.

Private User Claims

This feature provides a way for applications to identify the logged in user and their private claims. Private claims can be anything custom, defined by the organization, associated to users. To give a few examples, private claims can be:

  • application roles (user, manager, administrator), or
  • access to features (minimal, new, audit), or
  • associated to a/b testing (alpha, beta, stable)


Private Claims section can be accessed through the User Manager. In the example screenshot below, there are three different private claims with 3 values each.

A private claim can have many values and a given user can be associated to only one of those values. Each of the values can be either enabled or disabled, their state can be changed by clicking on them. The default state of newly added value is enabled.


The information about the user and their associated private claims are shared with the application via a HTTP header, X-0SNet-User. The private claims are namespaced by adding the prefix snet: to their names, for example: a private claim app will appear as snet:app in the JWT payload. A sample JWT payload is as follow:

    "iss": "0th Root Secure Network",
    "aud": "0th Root",
    "sub": "admin",
    "iat": 1647507494,
    "nbf": 1647507494,
    "exp": 1647509294,
    "email_verified": true,
    "email": "user@example.com",
    "name": "ADMIN: Example User",
    "snet:department": "operations",
    "snet:application": "stable",
    "snet:systems": "admin"

The JWT payload will include registered claims such as sub, name and email to identify the user along with the private claims.

The value of X-0SNet-User header is simply a base64 encoded JWT Payload (only) which can simply be decoded and parsed as a JSON text to access the claims. The sample code for integration can be found in Host Manager under subdomain configurations, see below.

For the header to be added to the requests, the option Add UserInfo should be enabled for the application (subdomain). Once enabled, all requests to the application will include the X-0SNet-User header.

Any change in user association to private claims through User Manager can take up to 30 seconds to reflect in the header due to an in-built cache.

Google Sign-In

Instead of 0SNet password authentication, Google OAuth can be used through the Google Sign-In (GSI) feature. When GSI is used, the user is prompted with a Sign In button, as shown below, instead of the usual username and password,

The email address of the user should match the Google account used for login.

Users can switch login method by clicking on the arrows. Older sign-in method has been deprecated and will be discontinued on March 31, 2023. Default is the newer identity services method, this can be changed in the backend using commands mentioned in quick reference.


Create a new client ID for 0SNet, in Google API Console, and specify the javascript origins. When 0SNet is configured for *.example.com, the javascript origins would be a.example.com, b.example.com and so on. Unlike 0SNet, wildcard is not supported, hence all internal applications and websites need to be added individually.

Enable GSI

The client ID can be set in 0SNet and GSI can be enabled using the command shown below,

sudo 0snet --gsi on [client-id]

Additional client IDs specific to domains can be added as follows,

sudo 0snet --gsi clientid [domain] [client-id]

To disable GSI at any point, the following command should be used,

sudo 0snet --gsi off

Do remember to restart 0SNet for changes to take effect,

sudo 0snet --stop && sudo 0snet --start

Process Changes

The user creation and certificate installation processes remain the same. Only at the time of login, the user is prompted with a Sign-In button instead of user name and password. Hence, with GSI, user doesn't need access to 0SNet password or username, expect at the time of certificate installation.


When GSI is enabled, 0SNet Server requires access to public internet to function. It verifies the connection to external servers using the trusted root certificates available on the server, typically at /etc/pki/tls/certs/ca-bundle.crt. All CAs are treated equally, so it is important to keep the CA bundle upto date.

Microsoft Sign-In

Instead of password authentication method, 0SNet can be configured to use Microsoft OAuth 2.0 through the Microsoft Sign-In (MSI) feature. When MSI is enabled, users will be prompted with a Sign In button to login, as shown below,

The email address of the user should match the Microsoft account used for login.


A client-id provided by Microsoft is needed to enable MSI in 0SNet. It can be found in Azure Active Directory.

An application need to be registered, as shown in the images below, Choose “Accounts in any organizational directory” ie., Multitenant, or whichever is relevant,

And, to support Sign-In across all sites configured under 0SNet, they need to be added under Redirect URIs for the application,

Enable MSI

The client-id can be set in 0SNet to enable MSI using the command shown below,

sudo 0snet --msi on [client-id]

To disable MSI at any point, the following command should be used,

sudo 0snet --msi off

Do remember to restart 0SNet for changes to take effect,

sudo 0snet --stop && sudo 0snet --start

Single Tenant

Optionally, if you choose Supported account types as Single tenant, tenant-id can be added with the command shown below,

sudo 0snet --msi tenant [tenant-id]

Do remember to restart 0SNet for changes to take effect,

sudo 0snet --stop && sudo 0snet --start

Process Changes

The user creation and certificate installation processes remain exactly the same. Only at the time of login, users will be presented with a Microsoft Sign-In button. Hence, with MSI enabled, password for the user will need to be used only for certificate installation.


Enabling MSI adds a dependency on Microsoft Login and Microsoft Graph API services. If any of them are down, users will not be able to login to 0SNet. This also essentially means, a public internet connection is required on the 0SNet server.

The connections to Microsoft services are verified using the trusted root certificates available on the server, typically at /etc/pki/tls/certs/ca-bundle.crt. All CAs are treated equally, so it is important to keep the CA bundle upto date.


0SNet incorporates a licensing system for easier distribution and sale of software. Every install of 0SNet comes with a license file which works for upto 3 users. You can review the license information using the following command,

$ sudo 0snet --license info
0throot license file                                      
     License Key : UzXE/CV82m6kysyrtYQfv6X13wX6tWdnR/IPeULoaroR
         Product : 0th Root Secure Network
          Domain : .corp.example.com
    Organization : Example Company Ltd.
  Date of Expiry : Dec 24, 2019 14:17 IST
           Users : 5
      Valid Upto : N/A

Contact us @ support@0throot.com for any queries.

License files are updated periodically (default: 1hr) through a cronjob. To update them manually, please run,

sudo 0snet --license sync

Command Line Interface (CLI)

0snet --cli <action> <arguments>

useradd, userreset, userdelete, userstatus, usergroup
    --name "full name"
    --email "email address"
    --userid "user-id"
    --group "group name"
    useradd --name <> --email <> --userid <> [--group <>] [--allow | --deny]
    userreset  (--userid <> | --email <>)
    userdelete (--userid <> | --email <>)
    userstatus (--userid <> | --email <>) (--enable | --disable)
    usergroup  (--userid <> | --email <>) --group <> (--add | --remove)


The --cli option of 0snet utility provides a command line interface to manage users within 0th Root Secure Network (0SNet). The utility can output in JSON format for easier integrations, refer to OUTPUT section for more details. And, to know more on possible integrations, refer to INTEGRATION section.

useradd can be used to add new user, it requires the --name, --email, --userid to be specified. user-id should be a single word with one or more of the following characters, a-z A-Z 0-9 - . _ :. Optionally, the newly created user can be added to access control groups by specifying the group name, with --group argument. Multiple groups can be specified by repeating --group. Additionally, --allow, --deny can be used to set appropriate exception to default access control statements for the new user. And, --nocert to add the user without certificate.

By default, newly added users are enabled, and they are not administrators. User manager should be used to set the added user as an administrator, if needed.

userreset will reset user certificate and credentials. The command outputs the new password, and it should be securely communicated to the user. When --email is used, all users matching the email address are reset.

userdelete can be used to delete user(s). All users matching the email address are deleted when using --email.

userstatus should be used when a user needs to be disabled, or when a disabled user needs to be re-enabled. On using the --email argument, all matching users are updated.

usergroup will add or remove user(s) from the specified list of groups. Multiple groups can be specified by repeating the --group argument. In case of a failure, the user(s) may be added or removed from some groups and not all.

The actions userstatus and usergroup are idempotent, and can be safely repeated, in case of any error.


In case of errors, the exit code of the command will be non-zero. The output format for useradd will be,

<user-id> <password>

And, when --json argument is specified, the output format changes to a JSON text, as follows,


In case of an error, the above JSON text will have code set to non-zero value and message will contain the description of the error.

For userreset, the output may contain multiple user-ids and passwords, one per line, when --email argument is used. The output JSON text can also have multiple user-ids as keys with corresponding passwords as values.


Scripts can be developed to process user information and pass on to 0snet-cli to perform a specific action. This could be a one-time task, such as for bulk addition of users, or could be a cron job for periodically adding and removing users.

A job management system could also be used, to securely login to server and run 0snet-cli to perform a specific action.

Exposing the actions of 0snet-cli as a service is NOT RECOMMENDED, and HIGHLY DISCOURAGED.


In the examples below, the first line is the command and the below lines are output of the command,

$ sudo 0snet --cli useradd --name "Example User" --email "user@example.com" --userid "example1"
example1 kfuKN16t
$ sudo 0snet --cli userstatus --userid "example1" --disable
updated user(s) successfully
$ sudo 0snet --cli userreset --userid "example1" --json
$ sudo 0snet --cli usergroup --userid "example1" --group "Employee" --add
updated users and groups successfully
$ sudo 0snet --cli userstatus --userid "example1" --enable --json
{"status":{"code":0,"message":"updated user(s) successfully"}}
$ sudo 0snet --cli userstatus --userid "example1"
example1 enabled
$ sudo 0snet --cli useradd --name "Example User (Mobile)" --email "user@example.com" --userid "example2" --group "Sales" --group "Employee" --deny --json
$ sudo 0snet --cli userreset --email "user@example.com"
example2 RqaHy9zH
example1 Scrn3HJ3
$ sudo 0snet --cli userdelete --userid "example2"
deleted user(s) successfully
$ sudo 0snet --cli usergroup --userid "example1" --group "Employee" --remove
updated users and groups successfully

Quick Reference


sudo 0snet --status
Check if server is running
sudo 0snet --start
Start the server
sudo 0snet --stop
Stop the server
sudo 0snet --graceful-stop
Gracefully stop the server
sudo 0snet --reload
Gracefully reload the server
sudo 0snet --stop && sudo 0snet --start
Restart the server


sudo 0snet --license info
Show details of current license file
sudo 0snet --license sync
Download new license file
sudo 0snet --license sync status
Display status of license file sync
sudo 0snet --license sync off
Disable automatic sync
sudo 0snet --license sync on
Enable automatic sync


sudo 0snet --gsi on [client-id]
Enable Google Sign-In
sudo 0snet --gsi off
Disable Google Sign-In
sudo 0snet --gsi method status
Current login method
sudo 0snet --gsi method sign-in
Choose Sign-In method (deprecated)
sudo 0snet --gsi method identity-services
Enable Identity Services (default)
sudo 0snet --gsi clientid
List configured client IDs
sudo 0snet --gsi clientid <domain> <client-id>
Set client ID for domain
sudo 0snet --gsi clientid <domain> unset
Unset client ID for domain
sudo 0snet --gsi openid status
Check OpenID document status
sudo 0snet --gsi openid sync
Download OpenID document and keys
sudo 0snet --gsi openid verify:<mode>
Change verification mode
Available modes: iv, i, v


sudo 0snet --msi on [client-id]
Enable Microsoft Sign-In
sudo 0snet --msi off
Disable Microsoft Sign-In
sudo 0snet --msi tenant [tenant-id]
Specify Tenant ID or "common"
sudo 0snet --msi openid status
Check OpenID document status
sudo 0snet --msi openid sync
Download OpenID document and keys
sudo 0snet --msi openid verify:<mode>
Change verification mode
Available modes: aiu, ai, iu, i, a


Secondary server actions

sudo 0snet --rsync check
sudo 0snet --rsync check on
sudo 0snet --rsync check off
Check for changes from primary server
sudo 0snet --rsync clean
Clear local state

Primary server actions

sudo 0snet --rsync key
Show SSH public key to add to Secondary servers
sudo 0snet --rsync users             <host> [ssh-options]
sudo 0snet --rsync users,login       <host> [ssh-options]
sudo 0snet --rsync users,login,certs <host> [ssh-options]
Sync data once
sudo 0snet --rsync users <host> :B:<bastion> [ssh-options]
Sync data once via <bastion> server
sudo 0snet --rsync config <host> [ssh-options]
Sync configuration once


sudo 0snet --letsencrypt mode
Get current mode
sudo 0snet --letsencrypt mode <mode>
Set Let's Encrypt mode
Values: auto, dns, off
sudo 0snet --letsencrypt 0snet <0snet-?>
Change reserved subdomain
Examples: 0snet-a, 0snet-1
sudo 0snet --letsencrypt 0snet on
Reset reserved subdomain to 0snet
sudo 0snet --letsencrypt hosts
Check current reserved subdomain in the hosts list


sudo 0snet --act tlsconfig <key> <cert>
Use custom TLS server certificate instead of Let's Encrypt issued certificates
sudo 0snet --opt authcert
sudo 0snet --opt authcert enforced
sudo 0snet --opt authcert configurable
Enforce TLS Client Certificate Authentication (or) Allow it to be configurable

High Availability

0SNet is a highly flexible and resilient system, it can be deployed on multiple servers across regions to form a cluster of servers. Due to the decentralized architecture, servers can run independently and are resilient to failure on other servers.


It uses a Primary-Secondary architecture where the administration happens on the Primary server while the serving happens through one or more Secondary servers. A push mechanism is used to transfer the data periodically to the Secondary servers.

To perform zero downtime maintenance, two or more Secondary servers can be placed under a load balancer. As long as a single Secondary server is running, there will not be any user impact.

Primary Access

0SNet uses rsync in multiple stages to transfer the data reliably to the Secondary servers. This requires the SSH key of Primary to be authorized on the Secondary servers. To obtain the SSH public key of Primary, the following command should be run.

sudo 0snet --rsync key                                    # Run on PRIMARY

The output of the above command needs to be added to /root/.ssh/authorized_keys on Secondary servers.

Initial Setup

Once 0SNet is installed on the Secondary servers, they should be configured using the command below,

sudo 0snet --rsync config <IP1>,<IP2>,...                 # Run on PRIMARY

To push the data to Secondary, the rsync command is as follows,

sudo 0snet --rsync users,login,certs,hosts <IP1>,<IP2>,...# Run on PRIMARY

Also, setup a cronjob to synchronize periodically. A sample cronjob is shown below,

0,30 * * * * root 0snet --rsync users,login,certs,hosts <IP1>,<IP2>,...

Secondary Configuration

On the Secondary servers, the following commands should be run,

sudo 0snet --opt authorigin any                           # Run on SECONDARY
sudo 0snet --rsync check on                               # Run on SECONDARY
sudo 0snet --letsencrypt mode off                         # Run on SECONDARY
sudo 0snet --license sync                                 # Run on SECONDARY

After running above commands, reboot the Secondary servers,

sudo systemctl reboot                                     # Run on SECONDARY

NOTE: If you are using legacy configuration of hosts, you may need to copy /etc/hosts entries to Secondary servers

DNS Configuration

Once a load balancer is configured for the Secondary servers, the DNS entries can be made as shown below,

    *.corp.example.com    A    <Load-Balancer-IP>
0snet.corp.example.com    A    <Primary-IP>

TLS Configuration

If you are using the default Let's Encrypt integration, run the commands below to change to DNS mode.

sudo 0snet --letsencrypt mode dns                         # Run on PRIMARY
sudo 0snet --letsencrypt auto                             # Run on PRIMARY
sudo 0snet --reload                                       # Run on PRIMARY

Alternatively, you can add your own wildcard TLS certificate as follows,

sudo 0snet --letsencrypt mode off                         # Run on PRIMARY
sudo 0snet --act tlsconfig <key-path> <certificate-path>  # Run on PRIMARY
sudo 0snet --reload                                       # Run on PRIMARY

Once the above steps are completed, the system is highly available and additional Secondary servers can be added to horizontally scale the system.

Let's Encrypt

0SNet provides tools for easier integration with Let's Encrypt TLS certificate. It internally uses Certbot client to obtain and manage Let's Encrypt issued TLS certificates.

NOTE: This feature is intended for setups where 0SNet server has a public IP and the default HTTP port 80 is available. In case of private setups, or where port 80 is used by a different program, the necessary domain validation cannot be done to get certificates.


Package for Certbot client is available on various distributions. On CentOS/RHEL 7.x, one can run the following command to install the EPEL repository,

sudo yum install epel-release

and install the certbot package,

sudo yum install certbot

In case, the client couldn't be installed through the native package manager, the following command can be used to download and install Certbot client.

The install of Certbot will be local to 0SNet. However, additional dependent packages will get installed, and/or upgraded, during the process. And, in case of any errors, you can attempt an experimental install with the option --debug, but make sure you have taken the necessary backups before using it.


0SNet is intended to secure all subdomains of the chosen domain, such as *.example.com. But, since, Let's Encrypt platform currently supports only multi-domain TLS certificates (upto 100 domains) over HTTP-01 challenge, and not wildcards, the list of subdomains used will be gathered by parsing the /etc/hosts file. This list of subdomains can be verified by running the command shown below,

It should be ensured that all required subdomains are part of the list, before fetching the TLS certificate. On adding a new subdomain, a new TLS certificate should be obtained (fetch) and enabled (on).


Let's Encrypt certificates are domain validated and are issued immediately. To obtain a new certificate, the fetch command should be run as follows,

During the process, 0SNet server will be stopped and started, with the service being offline for a few minutes.


A newly issued certificate is not automatically used by 0SNet. To enable Let's Encrypt certificate, the following command should be run,

sudo 0snet --letsencrypt on

And, to switch back to the previous certificate, ie., stop using Let's Encrypt certificate, run the command below,

sudo 0snet --letsencrypt off


0SNet checks the certificate for renewal daily and it gets automatically renewed. During the renewal process, which happen once in 2-3 months, the server may be offline for a few minutes.

The log messages are written to syslog, and is typically available at /var/log/messages, it should be checked for any errors during renewal.

Contact Us

0SNet is a product of 0th Root Software Research. For any questions (or) suggestions, please write to us at support@0throot.com

We are located at,

(Primary Address)
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10th Floor,
Bellary Rd, Hebbal,
Bengaluru - 560 024. (INDIA)

No.24, Tatia Nagar Phase -3,
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Chennai - 600 095. (INDIA)
+91 44 2653 2984

0th Root