Recently there were some well-documented problems with major sites, due to a major Register.com outage caused by a DoS attack. One interesting aspect of these attacks is that the sites themselves stayed up, although they seemed to be down to anyone who used Register.com's DNS servers. If you used OpenDNS, for example, all seemed fine. Or if you connected via IP address (bypassing the need for DNS) then you were unaffected.

The consequence of this is that if a provider of a Web API is simply monitoring their own server uptime, they will not detect an outage like this. The servers stay up. However, from many clients' points of view, the outage is very apparent. This can result in confusion and finger-pointing ("our service is not down - it works from here - the problem is your Internet connection!" / "But other sites are responding fine for me!", etc etc). Increasingly, business depend on Web APIs, and such finger-pointing is a waste of time.

Similar, if your ISP is running a slow connection to a Web API, then that is not the Web API provider's fault, and they will not alert you to the problem. So what is the answer?

The solution is to run a managed Cloud Gateway to manage and monitor the connection up to the Web API. Take the example of SalesForce.com. If an organization is linking its internal systems to SalesForce.com, then a Cloud Gateway provides monitoring, uptime, and metering information, as shown in yesterday's blog post. However, it goes further, since the Cloud Gateway has access to SalesForce.com uptime and response information from the point of view of the client, as shown below:



This means that if anything happens to the connection up to the SalesForce.com (or other) Web API, this is detected by the Vordel Gateway Cloud Edition. The administrator does not have to wait for an email from SalesForce.com. They are being proactive. Indeed, as in the case of the Register.com DNS attack, perhaps SalesForce.com is still available so they would not send any outage email, since from their point of view the service is available. But what matters to any organization is their own access to the Web API.

This alerting is setup using a simple policy configured on the Vordel Gateway Cloud Edition, shown below:



Notice that if the connection to SalesForce times out, the processing goes down the red "failure path" and results in an email being sent. All configuration is done using drag-and-join, so if you want to alert to SNMP, Syslog, Windows Event Log, etc, this is simply a matter of dragging in the appropriate filter and wiring it up in the policy.

Let's see this in action. I simulate a SalesForce network outage by simply pulling a cable. Now, this of course does not bring down the SalesForce APIs themselves. But they bring down network's access to SalesForce. So if I have a local database which is replicating SalesForce data, that connection is lost. So how do I find out about the problem?

Aha a new email on my Blackberry:



The email is from the Cloud Gateway:



Let's click on an alert and open it:



You can see that the Gateway identifies the client, their IP Address, and proactively tells me that the connection to SalesForce.com's Web API is down.

I can also configure a rule which will only send an alert once in a specific time period (to avoid receiving an "alert storm" on my Blackberry).

And finally, there is nothing Blackberry-specific about receiving an email alert from a Cloud Gateway - it just makes for a nice demo :-)

Check out the Vordel Gateway Cloud Edition here.