What's up with Macports' DNS?

[Dave Horsfall]

Happened twice now (but works some time later):

    mackie$ sudo port -v selfupdate
    --->  Checking for newer releases of MacPorts
      % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
				     Dload  Upload   Total   Spent    Left  Speed
    100    63  100    63    0     0    138      0 --:--:-- --:--:-- --:--:--   137
    MacPorts base version 2.10.7 installed,
    MacPorts base version 2.10.7 available.
    --->  MacPorts base is already the latest version
    --->  Updating the ports tree
    Synchronizing local ports tree from rsync://rsync.macports.org/macports/release/tarballs/ports.tar
    rsync: getaddrinfo: rsync.macports.org 873: nodename nor servname provided, or not known
    rsync error: error in socket IO (code 10) at /BuildRoot/Library/Caches/com.apple.xbs/Sources/rsync/rsync-52.0.1/rsync/clientserver.c(106) [receiver=2.6.9]
    Command failed: /usr/bin/rsync -rtzvl --delete-after --include=/ports.tar.gz --include=/ports.tar.gz.rmd160 --exclude=* rsync://rsync.macports.org/macports/release/tarballs/ /opt/local/var/macports/sources/rsync.macports.org/macports/release/tarballs/remote
    Exit code: 10
    Error: Synchronization of the local ports tree failed doing rsync
    Error: Couldn't sync the ports tree: Synchronization of 1 source failed
    Error: Follow https://guide.macports.org/#project.tickets if you believe there
    is a bug.
    Error: /opt/local/bin/port: port selfupdate failed: Couldn't sync the ports tree: Synchronization of 1 source failed
    mackie$ 

Why would the DNS be failing every week?

-- Dave