$ traefik version
Version:      dev
Codename:     cheddar
Go version:   go1.9.4
Built:        I don't remember exactly
OS/Arch:      darwin/amd64

$ brew info traefik
traefik: stable 1.5.2 (bottled), HEAD

$ traefik -c /tmp/foo/bar --debug
INFO[2018-02-25T04:22:15+01:00] Traefik version dev built on I don't remember exactly
INFO[2018-02-25T04:22:15+01:00]
Stats collection is disabled.
Help us improve Traefik by turning this feature on :)
More details on: https://docs.traefik.io/basics/#collected-data

DEBU[2018-02-25T04:22:15+01:00] Global configuration loaded {"LifeCycle":{"RequestAcceptGraceTimeout":0,"GraceTimeOut":0},"GraceTimeOut":0,"Debug":true,"CheckNewVersion":true,"SendAnonymousUsage":false,"AccessLogsFile":"","AccessLog":null,"TraefikLogsFile":"","TraefikLog":null,"LogLevel":"DEBUG","EntryPoints":{"http":{"Network":"","Address":":80","TLS":null,"Redirect":null,"Auth":null,"WhitelistSourceRange":null,"Compress":false,"ProxyProtocol":null,"ForwardedHeaders":{"Insecure":true,"TrustedIPs":null}}},"Cluster":null,"Constraints":[],"ACME":null,"DefaultEntryPoints":["http"],"ProvidersThrottleDuration":2000000000,"MaxIdleConnsPerHost":200,"IdleTimeout":0,"InsecureSkipVerify":false,"RootCAs":null,"Retry":null,"HealthCheck":{"Interval":30000000000},"RespondingTimeouts":null,"ForwardingTimeouts":null,"Web":null,"Docker":null,"File":null,"Marathon":null,"Consul":null,"ConsulCatalog":null,"Etcd":null,"Zookeeper":null,"Boltdb":null,"Kubernetes":null,"Mesos":null,"Eureka":null,"ECS":null,"Rancher":null,"DynamoDB":null,"ServiceFabric":null,"Rest":null,"API":null,"Metrics":null,"Ping":null}
INFO[2018-02-25T04:22:15+01:00] Preparing server http &{Network: Address::80 TLS:<nil> Redirect:<nil> Auth:<nil> WhitelistSourceRange:[] Compress:false ProxyProtocol:<nil> ForwardedHeaders:0xc4206ea160} with readTimeout=0s writeTimeout=0s idleTimeout=3m0s
ERRO[2018-02-25T04:22:15+01:00] Error opening listener listen tcp :80: bind: permission denied
FATA[2018-02-25T04:22:15+01:00] Error preparing server: listen tcp :80: bind: permission denied