Hi, It does not appear that you can access the 'addrFlags' returned by getAddrInfo, you get the exception: *** Exception: unpackBits: unhandled bits set: 8 Is this just a MacOS issue? Should I raise a ticket for it? Cheers Neil GHCi, version 6.10.2: http://www.haskell.org/ghc/ :? for help Loading package ghc-prim ... linking ... done. Loading package integer ... linking ... done. Loading package base ... linking ... done. Prelude> :m Network.Socket Prelude Network.Socket> getAddrInfo Nothing (Just "localhost") Nothing Loading package syb ... linking ... done. Loading package base-3.0.3.1 ... linking ... done. Loading package parsec-2.1.0.1 ... linking ... done. Loading package network-2.2.1 ... linking ... done. [AddrInfo {addrFlags = *** Exception: unpackBits: unhandled bits set: 8 Prelude Network.Socket>