certMode=flag.String("certmode","letsencrypt","mode for getting a cert. possible options: manual, letsencrypt")
certDir=flag.String("certdir",tsweb.DefaultCertDir("derper-certs"),"directory to store LetsEncrypt certs, if addr's port is :443")
hostname=flag.String("hostname","derp.tailscale.com","LetsEncrypt host name, if addr's port is :443")
logCollection=flag.String("logcollection","","If non-empty, logtail collection to log to")
runSTUN=flag.Bool("stun",true,"whether to run a STUN server. It will bind to the same IP (if any) as the --addr flag value.")
meshPSKFile=flag.String("mesh-psk-file",defaultMeshPSKFile(),"if non-empty, path to file containing the mesh pre-shared key file. It should contain some hex string; whitespace is trimmed.")