(Reuters) – Network equipment maker Infoblox Inc estimated second-quarter revenue below analysts’ average forecast, citing disappointing business with the U.S. government and fewer $1 million-plus transactions. The company’s shares fell 29 percent to $23.42 in extended trading. “While sales through the first two months of the quarter met our internal expectations, we experienced a much weaker January than expected,” Infoblox Chief Executive Robert Thomas said in a statement. …