Você pode excluir o local.dev do ProxyCommand, usando !
antes dele:
Host * !local.dev
ProxyCommand /usr/local/bin/corkscrew 127.0.0.1 8840 %h %p
De documentação do ssh_config :
If more than one pattern is provided, they should be separated by whitespace.
A pattern entry may be negated by prefixing it with an exclamation mark ('!'). If a negated entry is matched, then the Host entry is ignored, regardless of whether any other patterns on the line match. Negated matches are therefore useful to provide exceptions for wildcard matches.
A documentação também dizia:
For each parameter, the first obtained value will be used. The configuration files contain sections separated by ''Host'' specifications, and that section is only applied for hosts that match one of the patterns given in the specification. The matched host name is the one given on the command line.
Portanto, você também pode desabilitar o ProxyCommand para local.dev, sobrescrevendo o valor que você definiu em Host *
:
Host local.dev
HostName dev.myserver.com
User developer
ProxyCommand none