What's up with Macports' DNS?

[Joshua Root]

> 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 fromrsync://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: Followhttps://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?

Hard to say. When this happens for you, you could check if a different 
DNS server than what you usually use is able to resolve the hostname, 
with a command like:

host rsync.macports.org 1.1.1.1

(the second argument being the DNS server you want to use, with 
Cloudflare's being used in this example.)

You could also use a tool like DNS checker to see if the problem is 
widespread: <https://dnschecker.org/#CNAME/rsync.macports.org>

- Josh