captive portal checker

captive is a tiny cmdline tool to check if the system it is running on has working Internet access. Useful to detect captive portals on public WiFis and corporate networks. Checks http://captive.apple.com (which powers the Captive Portal Assistant on Apple devices).

Intended to be used in shell scripts: Single binary/no dependencies, cross-platform and returns the online status as exit code.

install

download executable from release page and copy it to a PATH location (i.e. /usr/local/bin or c:\windows\system32)

usage

Run captive (there are no parameters). It will return with exit code 0 when online or exit code 1 when offline.

Example:

$ captive
online
$ echo $?    #check exit code
0
$ ifconfig eth0 down    #break Internet connection
$ captive
offline
$ echo $?    #check exit code
1

build

with Go 1.13+ installed:

go get github.com/christian-korneck/captive/...

run with Docker

docker run --rm chko/captive