Connections Screen Slow to Display

In some environments selecting the management "connections" display screen on the central server can be slow to display. On busy servers with thousands of users a delay of several minutes is possible.

Users connecting and using GDS for data are not affected.


When the connections display builds the output list, it attempts to translate numeric IP addresses into textual form. For example the address would be converted to (example only, not real values) and the display will show "" as the remote users network address.

In order to perform this translation, the code calls DNS and requests reverse DNS Lookups. This involves the current server asking other machines (DNS servers) on your network and beyond to resolve addresses. Generally, this operation is very fast, however, it can take some time for a large number of reasons.

One of the most common reasons is that the reverse DNS lookup is not functioning correctly for all or some addresses. If the screen only displays numeric addresses, such as, then DNS is not configured at all. If only some addresses are failing then the "PTR" records in DNS are probably not defined (a reasonably common problem).

Background / Technical

Internally, the connections display uses the following logic for each connection to be displayed:

  1. Generate the dotted IP address from the inbound socket.
  2. call inet_addr() to convert this to lookup form.
  3. call gethostbyaddr(.... , AF_INET)
  4. If the above call succeeds, use the returned name, otherwise use the dotted IP address

Step #3 is the step that takes time.


The delay is due to external DNS configuration and not caused by GDS. Despite the delay, displaying connections in name form is more useful than dotted IP form, so no change will be undertaken in GDS.

There are numerous articles and books on configuring a DNS network which should be consulted. The topic is bigger than can be described in a support article.