[driverdan]

Shorting means borrowing the asset from someone else and selling it, not buying then selling.

I'd guess shorting isn't allowed but could be wrong. It certainly should be allowed.

[ewood]

There are secondary markets for most bonds so yes, you can short them. However most traders would do this through derivatives such as bond futures or ETFs.

[whatok]

Most traders would pick the optimal instrument to express their view which could end up being bond futures or ETFs but not always.