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WelcoYour alerts, by text.

Nagios SMS notifications to your on-call cellphone

Nagios SMS notifications put the host that is DOWN on the on-call admin's lock screen, before the help desk queue fills up. Nagios already emails each problem, so you give it one more contact: your Welco address. No plug-in, no SMS modem and no scripts on the Nagios box.

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  • One contact in contacts.cfg
  • No plug-in or SMS modem
  • No per-user fees

Works by email with

  • Nagios

Published:

A network map watched by Nagios: five hosts answer pings until srv14 goes critical (C: 1% free) and the monitor raises the alert. The email reaches Welco and the phone shows: “Welco: [srv14] Drive C: Disk Usage CRITICAL, 1% free at 2:41 AM. Reply STOP to opt out.”

Animation: a long Nagios alert email is trimmed into one short text: "Welco: [srv14] Drive C: Disk Usage CRITICAL, 1% free at 2:41 AM. Reply STOP to opt out."

What changes once Nagios can text

  • The night admin hears it

    A DOWN host after hours buzzes the one phone on call, not the whole contact group.

  • CRITICAL texts, WARNING waits

    Your notification options and a Welco rule decide which states are worth a text.

  • Readable on a lock screen

    Host, service, state and time in one line. No app to open and no VPN to log in.

  • Your email alerts stay put

    Existing contacts keep getting the same Nagios emails. Welco is simply one more recipient.

What you need before you start

Plan on about 15 minutes for one admin with shell access to the Nagios server. Other tools follow the same idea, as the server monitoring SMS alerts overview shows.

  • Nagios Core or Nagios XI that already emails alerts. If alert mail reaches your inbox now, this part is done.
  • A Welco account with your business verified, plus your Welco address. Start free if you don't have one yet.
  • Admins who joined from a Welco invite with their own cellphone, on any Canadian carrier. Each one replies YES before any Nagios text reaches them. No app is needed.

How to set up Nagios SMS notifications in 5 steps

These steps use Nagios Core's config files. On Nagios XI, build the same contact under Configure and Contacts.

  1. Approve Nagios as a sender in Welco

    Add the address Nagios mails from, such as nagios@monitor.example.net, to your approved-sender list. Mail from any other address is refused, so a stranger can't text your admins.

  2. Define a contact for your Welco address

    In contacts.cfg, add a contact whose email is your Welco address. Reuse the notification commands your other contacts run, notify-host-by-email and notify-service-by-email.

    • Set host_notification_options to d,u,r for down, unreachable and recovered hosts.
    • Set service_notification_options to c,r. Leaving out w keeps WARNING states off the phone.

  3. Add the contact to a contact group

    Put the new contact in the group that covers the hosts you care about, such as admins or on-call. Only hosts and services that notify that group will produce texts.

  4. Verify the config and restart Nagios

    Run nagios -v /usr/local/nagios/etc/nagios.cfg. Once it reports zero errors, restart the Nagios service so the contact goes live.

  5. Send a custom notification as a test

    Open any service in the web interface and pick Send custom service notification. Switch on Welco's dry-run mode first to see the result in the feed without spending a credit.

Your next Nagios PROBLEM can be a text

Verify your business, then paste your Welco address into one contact definition.

7-day free trial, 15 message creditsCard required for verificationNo charge for 7 daysEmail reminder before billing

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What a Nagios alert looks like as a text

Nagios host alerts repeat the notification type, address and full date. Welco keeps the host, the state and the time, so the message fits one lock screen.

Alert email from nagios@monitor.example.net, subject “** PROBLEM Host Alert: fw-branch-moncton is DOWN **”. Welco trims it to one text of 87 characters: “Welco: [fw-branch-moncton] Host DOWN, unreachable at 11:05 PM. Reply STOP to opt out.”

Text received: Welco: [fw-branch-moncton] Host DOWN, unreachable at 11:05 PM. Reply STOP to opt out.

Characters243871 credit

Animation: the alert email "** PROBLEM Host Alert: fw-branch-moncton is DOWN **" is trimmed into one text: "Welco: [fw-branch-moncton] Host DOWN, unreachable at 11:05 PM. Reply STOP to opt out."

Trimming is a rule you control. See how one-text trimming cuts a long email down to the part that matters.

Keep Nagios texts quiet until they matter

Most noise is fixed in Nagios itself. Welco handles the rest on the email it receives. This is how a US credit union texts overnight failures to one admin.

  • Night alerts to the night phone

    Use time-of-day routing so daytime problems reach the whole team and after-hours ones reach whoever is on call.

  • Recoveries stay in email

    Keep r if you like recovery texts. Otherwise a keyword rule drops mail that says RECOVERY.

  • Flapping checks stay quiet

    Leave f out of the notification options so FLAPPINGSTART and FLAPPINGSTOP never become texts.

  • Maintenance windows stay silent

    During scheduled downtime Nagios holds problem notifications. Leave s out too, so downtime start and end notices don't text anyone.

  • Repeats on your terms

    Nagios re-sends an unfixed problem every notification_interval minutes. Set it to 0 for a single text per problem.

  • One text when a switch dies

    Parent and child host settings stop hosts behind a dead switch from alerting. Welco's burst limits per phone cap whatever still gets through.

If the Nagios text doesn't arrive

Most misses come from one of four places. Work down the list in order.

No email left the server

Where to look
Nagios hands alerts to the local mail program. Test the mail command from the Nagios host.

The Welco feed shows a refused message

Where to look
The sender isn't approved yet. Add the exact From address Nagios uses.

The feed shows the alert but no text

Where to look
That phone hasn't replied YES yet, or its owner replied STOP.

A delivery failure in the feed

Where to look
Welco's plain-English delivery status names the cause, such as a landline number.

Frequently asked questions

Do I need a Nagios plug-in or an SMS modem to send texts?

No. Welco works from the email notifications Nagios already sends. You add one contact with your Welco address and Welco turns each alert email into a text. Nothing is installed on the Nagios server.

Can different hosts text different admins?

Yes. One Welco address can reach several phones, and each phone gets an alert once. Alert rules can send firewall hosts to the network admin and everything after 6 p.m. to the on-call phone.

Will recovery, flapping and downtime notifications become texts?

Only the types you allow. Nagios sends what the r, f and s options permit, and a Welco rule can drop anything that says RECOVERY. Many teams keep just d,u and c on the Welco contact.

Can the on-call admin acknowledge a Nagios problem by replying?

No. A text reply is emailed back to the alert's sender, which tells the team who is on it. Acknowledge the problem in the Nagios web interface so notifications stop there.

Does this work with Nagios XI as well as Nagios Core?

Yes. Nagios XI sends the same kind of alert emails. Create a contact with your Welco address under Configure and Contacts, add it to a contact group, then send a test notification.

What does a Nagios text cost?

Plans have no per-user fees, no hardware and no setup fee. A short alert uses one message credit, and long ones use more unless trimmed. Try Nagios texts free for 7 days with 15 credits, and your card is checked, not charged, until you approve a plan. See pricing for plans in US dollars, with no overage charges.

Get your next Nagios alert as a text

Add one contact in Nagios. Welco does the rest.

Text me my Nagios alertsBook a demo

7-day free trial, 15 message creditsCard required for verificationNo charge for 7 daysEmail reminder before billing