as of commit 71fb5e82f3e9a1501b4dc2430f9193ee5d176c82, MIDAS RPC and the mserver 
listen for connections both on IPv4 and IPv6. mserver clients and MIDAS RPC 
clients can connect to MIDAS using both IPv4 and IPv6. In the default 
configuration ("/Expt/Security/Enable non-localhost RPC" set to "n"), IPv4 
localhost is used, as before. Support for IPv6 is a by product from switching 
from obsolete non-thread-safe gethostbyname() and getaddrbyname() to modern 
getaddrinfo() and getnameinfo(). This fixes bug 357, observed crash of mhttpd 
inside gethostbyname(). K.O.