Simple Failover continuously monitors your network servers, notifies you of any trouble, and redirects traffic to standby servers when needed.
Monitoring is done by polling (sending requests to) your servers and evaluating the
response against configurable criteria (e.g., web page must contain specific text).
- Polling method "Ping (ICMP ECHO)"
The advantage of this polling method is that it is very simple and light weight (no TCP connection overhead),
it uses very little bandwidth (ping packets are very small), and it can be used for any type of Internet service.
- Polling method "HTTP"
You can use either HEAD or GET requests. Specify a URL, evaluate response code, response length and response content (GET requests).
- Polling method "TCP connect"
Connect to any TCP port and optionally evaluate the content of the returned greeting.
Pre-configured values are available for "FTP", "SMTP", "POP3", "NNTP", and "IMAP".
- Polling method "DNS"
Monitor DNS servers - optionally evaluate the content (IP address) in the returned DNS response.
- Polling method "Execute command line"
Use your own program or script to poll the servers. Simple Failover can evaluate the exit code and/or standard output (STDOUT) from
your program / script in order to determine if the server poll was successful.
It is possible to run executables (.exe) and batch (.bat) files directly, as well as most types of script languages through
Windows Scripting Host (WSH) by executing "cscript.exe".
- Configurable polling intervals
Simple Failover can be configured to perform the server monitoring at user
defined intervals to match your needs.
- Option to poll a different server IP address than the IP address set in DNS
For monitoring servers behind same NAT router as Simple Failover, you can specify both public and private IP addresses for a server.
- Polling history recorded for each server
For quick review of each server's history and evidence of server reliability.
Stored in a SQL Server Compact database. Can be exported to disk in csv format.
Notifications can be sent whenever a server is not responding as expected (after a configurable number of retries), when a server comes back online, when a DNS update fails, and when a DNS updates succeeds after a previous failure.
Simple Failover can send notifications to multiple recipients using multiple methods for each event.
- Notification method "e-mail"
All parts of the e-mail can be customized. SSL / TLS and SMTP authentication is fully supported.
- Notification method "HTTP"
Simple Failover will send the notification data via HTTP (GET or POST). HTTP request content can be fully customized. Supports SSL and HTTP authentication
Use this to trigger a script on a web-server to handle notification - for example an SMS / texting service.
- Notification method "Execute command line"
Use your own program or script to send the notification.
It is possible to run executables (.exe) and batch (.bat) files directly, as well as most types of
script languages through Windows Scripting Host (WSH) by executing "cscript.exe".
- Notification method "Windows Event log"
Writes an entry to the Windows Event Log (see Windows Control Panel / Administrative Tools / Event Viewer).
This makes it possible to take advantage of features (such as notification) of
the Windows Event Log service as well as other tools built to work with this.
- Balloon tip notification / Sound notification
Simple Failover can display a balloon tip notification from the system tray and or play a sound to attract attention whenever a problem is detected.
Redirection / DNS updates
Redirection of server traffic is done via DNS by always pointing your domain name to the IP address
of a functional server. When needed, Simple Failover can either dynamically update the DNS records
on your DNS servers (practically any brand of DNS server), or it can itself serve as a front-end DNS server.
- Serve DNS requests directly
Use Simple Failover as your Internet facing DNS server. Any DNS request received that Simple Failover does not have data for is forwarded on to your real DNS server.
This eliminates the need to update DNS records on the DNS server (also supported).
- DNS update method "Dynamic update via DNS protocol"
Sends updates directly to the DNS server via the DNS protocol (UDP port 53), optionally secured/authenticated using TSIG signatures.
- DNS update method "HTTP"
Sends updates to the DNS server via HTTP.
This might be used for example with a dynamic DNS service provider who offers an HTTP interface to update DNS records.
SSL and HTTP authentication is fully supported.
HTTP response status code and content can be evaluated for determine success.
- DNS update method "Execute command line"
Use your own program or script to do the update.
It is possible to run executables (.exe) and batch (.bat) files directly, as well
as most types of script languages through Windows Scripting Host (WSH) by executing "cscript.exe".
- DNS update method "Microsoft DNS server (dnscmd.exe)"
Updates a Microsoft DNS server using the Microsoft "dnscmd.exe" command line tool behind the scenes.
Can also securely update a remote Microsoft DNS server via the Simple Failover - Microsoft DNS update agent.
- DNS Round Robin load balancing
Simple Failover can update DNS so that all functional servers for a service
receive traffic on a rotating basis (utilizing DNS round robin), or it can
update DNS so that only one server receives traffic (by server priority) if you
have a primary server and one or more backup servers.
- Weighted DNS Round Robin
When serving DNS requests directly, you can balance traffic sent to your servers - specifying how much relative load each server should receive.
- Configurable DNS TTL values
DNS records TTL (time to live) values can be configured to control DNS caching.
- Support for DNS wildcard host names (*.hostname.tld)
No need to enter a long list of sub-names.
Simple Failover has an intuitive classic Windows desktop application user interface.
The main window is divided into three main tabs: Server set tab, Log
tab, and Problems tab. See screen shots.
- Main window - Server sets tab
The Server set tab consists of an explorer like list of the defined server sets
on the left and associated details on the right.
- Main window - Log tab
See what's going on behind the scenes - live.
The Log tab shows what is currently happening, and how the
program reacts to the monitoring process in real time.
- Main window - Problems tab
The Problem tab lists all current problems detected.
- Ping a server
When a server appears to be down, for many, the first trouble shooting step is to open a command prompt and ping the server IP address.
You can ping an individual server in Simple Failover simply by hitting the "Ping" button under the server in the main window Server Sets tab.
- IDNs (Internationalized Domain Names)
Enter and view host names with native international characters.
- HTTP API interface (Professional / Unlimited licenses only)
Nearly all the functions found in the Simple Failover UI are also available through a REST / JSON based HTTP API.
It is possible to create/update server sets, retrieve status information, and control most other functions in Simple Failover via the HTTP API.
This opens the possibility of creating your own web-interface to Simple Failover, and/or integrating it with your existing hosting solutions.
All data is exchanged in JSON format, and the commands and data formats are described in detail in the documentation.
Full support for IPv6 - polling, DNS updating, etc.
- Runs as Windows Service
Simple Failover runs as a Windows Service so that it continues
monitoring and failover protecting your servers without anyone being logged into the computer it is
- Configuration file in JSON format
Simple Failover uses one configuration file (in JSON format) to store all the
programs options and server sets definitions.
This makes it easy to interface with Simple Failover from other software etc.
- Support for latest Windows versions including 64 bit Windows
Simple Failover runs on Windows Vista / Server 2008 and later, including 64 bit Windows.