When You Can't Reach an IP Address
The annoying alert below is often encountered by Firefox users, but it is particularly frustrating in an Industrial Ethernet network that contains few devices.
As listed above, the site could be "temporarily unavailable" a nice way of saying the targeted device is offline, perhaps due to a malfunction. The second suggestion above to "check your computer's network connection" is always good advice. The third caution about a "firewall or proxy" is less likely to be an issue and usually you are aware of such situations anyway. And for those of you still using Internet Explorer (IE), the alert below gives similar suggestions.
The third suggestion from the IE alert above is perhaps the most significant to Industrial Ethernet users. Mistyping is among the most common cause of errors. But here is where you may encounter a most surprising and very simple mistake one that often goes quite unrecognized until time has been wasted investigating other, more-expected issues.
This common mistake alluded to above occurs when you are careless with your list of network IP addresses. Have you ever failed to realize that you are typing in the very same address of the machine at which you are typing? Yes, making this simple mistake will yield either of the alerts shown above. Before you start checking network connections and other issues, confirm that you are not targeting your own IP address!