Private equity firm Thoma Bravo is taking strong interest in buying Seattle-based F5 Networks, The Post has learned.

F5 Networks, according to a report last month, hired Goldman Sachs to work through several takeover approaches it had received.

The company, whose application delivery networking devices control traffic to Web sites and improve security, saw it shares spike nearly 13 percent on June 7 in the wake of the report from Reuters on the Goldman hire, to $123.94, has eased more recently.

In Tuesday morning trading, shares of F5, which has a market cap of $7.7 billion, were off 2 cents to $115.82.

Thoma Bravo has been a very active buyer of late, agreeing to acquire five companies since June — including Qlik Technologies for about $3 billion.

However, the firm, currently looking to raise a $7 billion fund, would be leading its biggest deal ever if it wins F5.

“A sale might have been more interesting a year ago,” a leading tech banker who is aware of F5 sales’ process, told The Post, explaining why some strategic buyers may not be interested.

“F5 missed an opportunity” to get a big price, he said.

Of course, there is no guarantee F5 will accept any potential offer and a sale is from assured.

Neither F5 nor Thoma Bravo returned calls for comment.