linkchk is a network interface link ping monitor. It supports both IPv4 and IPv6. It works by monitoring the routing table and pinging the gateway (next hop) of a network interface. When the link is up and functioning the ping time is displayed in a small gtk window, otherwise the link status is displayed. linkchk can also run in a tty.
I wrote this because of my unreliable ISDN TA which has a tendency to freeze my ppp link intermittently. So I wanted a quick and convenient way of monitoring the link's state.
2001-11-14 linkchk-0.02 released: source tarball, i386 rpm and source rpm
2001-10-18 linkchk-0.01 released: source tarball, i386 rpm and source rpm
2001-08-17 initial release: linkchk-0.00 and gzip'ed Linux binary(The binaries probably require a newish Linux distribution to work.)