Nagios SMS and Voice alert notifications

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I have recently been asked to review the options for SMS/Voice notifications that can be integrated into a customer’s Nagios environment. Whilst there are plenty of ways to do this, I narrowed it down to these three methods:

1. SMS Alerting via direct integration or e-mail parsing:

SMS alerts are sent using third party hosted environment, you just have to configure Nagios to send an email to a specific address similar to your existing e-mail notification rules. When the email has been received, an alert procedure is automatically triggered in order to notify you about the incident. There are different services with different capabilities, one of the providers allows you set rules for alerting, for e.g. you can add team based alert procedures, i.e. If an alert about a Cisco router is received, then the “Network Team” is alerted by SMS. If they don’t acknowledge the alert within 5 minutes, the “Backup Network Team” is alerted by voice call and the manager is notified by email, etc.

Hosted solutions may not suit businesses that don’t want their alerts (which may contain sensitive information) flowing through the inter web and hence you will need to consider an in-house implementation. Derdack’s Enterprise Alert is an advanced “rule based” notifications system that can be hosted in-house and hence putting you in control of your data. The product also offers native integration to various monitoring systems such as IBM Tivoli Monitoring, IBM Tivoli Netcool OMNIbus, Microsoft System Center (SCOM, SCSM, SCO), HP Operations Manager, HP Systems Insight Manager, Solarwinds, Nagios, Zenoss, Nimsoft, etc. It’s likely you may have a combination of these products deployed in your estate and Enterprise Alert can centrally manage the alerts from these systems.


Enterprise Alert offers a lot more than just SMS/Voice notification capability. Use of Smartphone apps for iOS, Android, etc. and deep integration with various systems management products allows for Remote IT and System Control, making it a very powerful and must-have tool for your IT operations staff. However, this is out of the scope for this blog and if you like to find out more about Enterprise Alert, click here.

There are other notification systems that are fairly simple, which requires you to send an e-mail to a specific address, it is mapped to a specific phone number and content of email is sent via SMS or read as a message via a voice call.

2. Third-party SMS gateway:

These services normally offers APIs that can be used to send SMS notification or make voice calls. You will need to configure Nagios to use custom notification channel that passes in variables such as summary, destination, etc. and this can be used to call a PHP script that uses HTTP GET, which is customized with what your hosted SMS gateway provider requires. When an alert comes in, this procedure will be kicked off. However, there is no alert intelligence that some of the services in the previous category can provide.

3. In-house SMS gateway:

Same as 2., except you host your own SMS gateway and obviously need network accessibility between Nagios and the SMS modem. Nagios offers native integration into Nagios XI if you use the MultiTech iSMS GSM modem. But it doesn’t do 2-way event processing and hence there is no intelligence behind it and hence rely on Nagios’s notification rules and behaves same as hosted SMS gateway.

Obviously, you will bear the hardware cost but you will be paying network charges for SMS being sent rather than a premium price that hosted services would charge you and that would eventually pay off the initial investment. If you are expecting a large volume of alerts then this option would be a good investment. I have taken the liberty to give you an overview of the costs involved. Whilst this may differ from service to service, it should give you a rough idea of what you would be looking at:

Estimations based on 2000 notifications in a month:

For Multitech iSMS based integration:

Item Price
Hardware Cost £400 (Ex-VAT)
SMS Charges[1] £10/month (Ex-VAT)

[1] Based on Unlimited SMS package on Vodafone UK contract. (Nothing less than ‘Unlimited’ is available!)

For Hosted integration:

Item Price
Hardware Cost N/A
SMS Charges[2] £100/month (Ex-VAT)

[2] Based on average 5p/message on various services.

And so, in a period of 12 months – hosted service would cost you around £1200 whilst In-house implementation would cost you £520 (including hardware). Extrapolate to 24 months and hosted service costs £2400 whilst In-house implementation costs £640 (including hardware).


Small and medium sized businesses with low alert volumes may be attracted to Option 2. or 3. and that is exactly what the customer I was working with ended up choosing. However, I strongly recommend to take a look at Derdack’s Enterprise Alert, as it goes beyond just alerting and also deals with remote actions that opens a whole new avenue that you may have not thought about.

Whilst I have explored these options in the context of Nagios, these methods can obviously can be implemented with other system/event management systems as well.

If you are interested in discussing the subject further, please feel free to leave comments on this post or contact me directly at:

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