Palo Alto Networks provided some good news today amid a stormy earnings season, but investors might have been expecting even more from the security vendor, as its stock was down as much as 11 percent in after-hours trading.

Results for Palo Alto's third quarter, ended April 30, were fine. Revenues of $345.8 million exceeded the company's forecast of up to $339 million.

For its fourth quarter, Palo Alto is expecting growth of 36 to 37 percent compared with the previous year — meaning revenues of $386 million to $390 million.

But investors seemed primed for an even bigger forecast. Yesterday, analyst Catharine Trebnick of Dougherty & Co. raised her fourth-quarter prediction to $391.8 million, citing a "very substantial pipeline of deals and opportunities." For example, she reported in a research note that Palo Alto has been earning more business from service providers and is in a bakeoff against Cisco for two major enterprise deals.

Much of the news out of networking earnings reports has been glum. On their recent earnings calls, Brocade, Cisco, and Juniper all cited tough economic conditions and/or delays in orders from service providers.

And one security vendor, FireEye, recently reported some disappointing results as well. Company officials blamed a faster-than-expected shift to subscription pricing models.

Palo Alto, by comparison, has been an oasis, consistently reporting strong earnings. (Arista Networks, which depends more on data centers and cloud vendors than on service providers, has been another exception.)

On Palo Alto's earnings call, CEO Mark McLaughlin did acknowledge the tough environment, with customers weighing the uncertainty behind macroeconomic factors such as the price of oil or the Chinese economy. "They're doing more inspection on deals," lengthening the time it takes to close a sale, he said.

For its third quarter, Palo Alto's revenues of $345.8 million compared with $234.2 million for the same quarter a year ago.

Third-quarter net losses were $70.2 million, or 80 cents per share, compared with year-ago losses of $45.9 million, or 56 cents per share.

Non-GAAP net income of 42 cents per share matched the analysts' estimate compiled by Thomson Financial.