Long delays when establishing RMI connection after losing network connectivity

On Windows® operating systems, if you are using the remote method invocation (RMI) port to connect to your WebSphere® Application Server v6.x, you might experience long delays establishing a connection to the server after losing network connectivity. This can occur even if the server is local and the network connectivity is lost only temporarily, which is common in a wireless network environment. If you know the server is started, but the status in the Servers views displays Stopped or Started, try to see if you can establish a connection to the server by switching the server connection from RMI to SOAP. The status of the server should change to Started.
There are a couple of options that are available to establish connection to a server in a wireless network environment:
  • The easiest and safest option, is to switch your connection to use the SOAP port. After losing network connectivity, SOAP connections has the ability to recover more quicker compared to a RMI connection.
  • If you must use a RMI connection, you can try to modify the default settings pertaining to the Domain Name System (DNS) caching on the Windows operating system. For details, refer to the following Microsoft® support article: http://support.microsoft.com/kb/318803

    Windows operating system has a built in DNS caching that maintains resolved host names. This allows for a faster turnaround when issuing DNS lookups. However there is a disadvantage to this, which is if a DNS lookup fails. The Windows operating system caches the failed value, for a default time of 300 seconds. So even if the DNS server can resolve the lookup shortly thereafter, it does not actually attempt the lookup until the cache time expires. As a result, a failed DNS lookup with default settings can take as long as 5 minutes before a true retry is attempted in the lookup. Setting the cache time to 0 seconds forces the Windows operating system to never cache failed DNS lookup queries, and allow the reconnect to occur as soon as the DNS becomes available.

The following is an example of disabling DNS caching for failed lookups on Windows operating systems:
In the following registry key:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Dnscache\Parameters
Add one of the following registry value:
  • For Windows XP or 2003:
    "MaxNegativeCacheTtl"=dword:00000000 
  • For Windows 2000:
    "NegativeCacheTime"=dword:00000000 

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