Java components in ArcIMS such as Java Viewer, ArcExplorer Java, Administrator, and Designer or custom MapObjects Java client applications can connect to ArcIMS Server through the ArcIMS Servlet Connector using two types of URLs:
1) Partial URL:
2) Full URL:
In the case of a partial URL, Java client applications append the rest of the URL that is needed. However, to know whether the URL is full or partial, it first does a ping test and as a result, the Web server receives a request similar to the following:
This does not harm the Web server and provides flexibility to ArcIMS or MapObjects Java client applications. This is why you'll notice ?cmd=ping requests that do not appear to go to a valid URL in your Web server logs.