ssh não reconhece o nome do host definido no arquivo de configuração [closed]

Question

Meu ssh não pode mais resolver meu nome de host. Tudo estava funcionando bem até que eu fiz uma atualização de segurança no meu Ubuntu v16.04. Eu tento fazer ssh <myhost> e receber o erro

ssh: Could not resolve hostname <myhost>: Name or service not known

Meu arquivo ~/.ssh/config é semelhante a este

Host <myhost>
    Hostname <host>
    User <username>

Se eu tentar host <myhost> , obtenho

Host <myhost> not found: 3(NXDOMAIN)

Eu não tenho ideia do que está acontecendo. Evidentemente, o ssh não pode resolver os campos dentro do meu arquivo de configuração? Eu tentei fazer strace ssh <myhost> , mas acabei de receber um monte de leitura que eu não consigo entender. Fazendo

ssh <username>@<myhost>

funcionará no entanto cada vez que eu fizer isso recebo o seguinte

Could not create directory '/.ssh'.
The authenticity of host '<hostname> (<ipaddress>)' can't be established.
ECDSA key fingerprint is <fingerprint>.
Are you sure you want to continue connecting (yes/no)? yes
Failed to add the host to the list of known hosts (/.ssh/known_hosts).

Alguma idéia do que poderia ser?

EDIT: Eu também devo mencionar que estou usando chaves ssh

A saída de ls -la ~/.ssh é:

-rw-rw-r--  1 <user> <user>   64 Aug 10 16:20 config
-rw-------  1 <user> <user> 1244 Jul 18 23:51 known_hosts

A saída de /bin/env

XDG_VTNR=7
XDG_SESSION_ID=c2
CLUTTER_IM_MODULE=xim
XDG_GREETER_DATA_DIR=/var/lib/lightdm-data/<user>
SESSION=gnome
GPG_AGENT_INFO=/home/<user>/.gnupg/S.gpg-agent:0:1
SHELL=/bin/bash
TERM=xterm-256color
XDG_MENU_PREFIX=gnome-
VTE_VERSION=4205
QT_LINUX_ACCESSIBILITY_ALWAYS_ON=1
GJS_DEBUG_OUTPUT=stderr
WINDOWID=62914566
UPSTART_SESSION=unix:abstract=/com/ubuntu/upstart-session/1389308713/5901
GNOME_KEYRING_CONTROL=
GJS_DEBUG_TOPICS=JS ERROR;JS LOG
GTK_MODULES=gail:atk-bridge
USER=<user>
LS_COLORS=rs=0:di=01;34:ln=01;36:mh=00:pi=40;33:so=01;35:do=01;35:bd=40;33;01:cd=40;33;01:or=40;31;01:mi=00:su=37;41:sg=30;43:ca=30;41:tw=30;42:ow=34;42:st=37;44:ex=01;32:*.tar=01;31:*.tgz=01;31:*.arc=01;31:*.arj=01;31:*.taz=01;31:*.lha=01;31:*.lz4=01;31:*.lzh=01;31:*.lzma=01;31:*.tlz=01;31:*.txz=01;31:*.tzo=01;31:*.t7z=01;31:*.zip=01;31:*.z=01;31:*.Z=01;31:*.dz=01;31:*.gz=01;31:*.lrz=01;31:*.lz=01;31:*.lzo=01;31:*.xz=01;31:*.bz2=01;31:*.bz=01;31:*.tbz=01;31:*.tbz2=01;31:*.tz=01;31:*.deb=01;31:*.rpm=01;31:*.jar=01;31:*.war=01;31:*.ear=01;31:*.sar=01;31:*.rar=01;31:*.alz=01;31:*.ace=01;31:*.zoo=01;31:*.cpio=01;31:*.7z=01;31:*.rz=01;31:*.cab=01;31:*.jpg=01;35:*.jpeg=01;35:*.gif=01;35:*.bmp=01;35:*.pbm=01;35:*.pgm=01;35:*.ppm=01;35:*.tga=01;35:*.xbm=01;35:*.xpm=01;35:*.tif=01;35:*.tiff=01;35:*.png=01;35:*.svg=01;35:*.svgz=01;35:*.mng=01;35:*.pcx=01;35:*.mov=01;35:*.mpg=01;35:*.mpeg=01;35:*.m2v=01;35:*.mkv=01;35:*.webm=01;35:*.ogm=01;35:*.mp4=01;35:*.m4v=01;35:*.mp4v=01;35:*.vob=01;35:*.qt=01;35:*.nuv=01;35:*.wmv=01;35:*.asf=01;35:*.rm=01;35:*.rmvb=01;35:*.flc=01;35:*.avi=01;35:*.fli=01;35:*.flv=01;35:*.gl=01;35:*.dl=01;35:*.xcf=01;35:*.xwd=01;35:*.yuv=01;35:*.cgm=01;35:*.emf=01;35:*.ogv=01;35:*.ogx=01;35:*.aac=00;36:*.au=00;36:*.flac=00;36:*.m4a=00;36:*.mid=00;36:*.midi=00;36:*.mka=00;36:*.mp3=00;36:*.mpc=00;36:*.ogg=00;36:*.ra=00;36:*.wav=00;36:*.oga=00;36:*.opus=00;36:*.spx=00;36:*.xspf=00;36:
QT_ACCESSIBILITY=1
XDG_SESSION_PATH=/org/freedesktop/DisplayManager/Session0
XDG_SEAT_PATH=/org/freedesktop/DisplayManager/Seat0
SSH_AUTH_SOCK=/run/user/1389308713/keyring/ssh
DEFAULTS_PATH=/usr/share/gconf/gnome.default.path
XDG_CONFIG_DIRS=/etc/xdg/xdg-gnome:/usr/share/upstart/xdg:/etc/xdg
PATH=/home/<user>/bin:/home/<user>/.local/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin:/opt/puppetlabs/bin:/opt/ParaView-5.5.0-Qt5-MPI-Linux-64bit/bin/
DESKTOP_SESSION=gnome
QT_IM_MODULE=ibus
QT_QPA_PLATFORMTHEME=appmenu-qt5
XDG_SESSION_TYPE=x11
JOB=dbus
XMODIFIERS=@im=ibus
GNOME_KEYRING_PID=
LANG=en_AU.UTF-8
GDM_LANG=en_AU
MANDATORY_PATH=/usr/share/gconf/gnome.mandatory.path
IM_CONFIG_PHASE=1
GDMSESSION=gnome
KRB5CCNAME=KEYRING:persistent:1389308713
SESSIONTYPE=gnome-session
GTK2_MODULES=overlay-scrollbar
HOME=<user>
XDG_SEAT=seat0
SHLVL=1
LANGUAGE=en_AU
GNOME_DESKTOP_SESSION_ID=this-is-deprecated
XDG_SESSION_DESKTOP=gnome
LOGNAME=<user>
QT4_IM_MODULE=xim
XDG_DATA_DIRS=/usr/share/gnome:/usr/local/share:/usr/share:/var/lib/snapd/desktop
DBUS_SESSION_BUS_ADDRESS=unix:abstract=/tmp/dbus-me2bC1MiXg
LESSOPEN=| /usr/bin/lesspipe %s
INSTANCE=
XDG_RUNTIME_DIR=/run/user/1389308713
DISPLAY=:0
XDG_CURRENT_DESKTOP=GNOME
GTK_IM_MODULE=ibus
LESSCLOSE=/usr/bin/lesspipe %s %s
XAUTHORITY=/home/<user>/.Xauthority
_=/usr/bin/env
OLDPWD=<user>