Introduction:

Wildcat! has a built-in DNS client resolver and uses a TTL-based cache to reduce DNS lookup overhead. TTL (Time To Live) is provided by all DNS lookups to indicate when the record expires. It would be waste to continue lookup up records when the result will not change until the TTL expires. So WcDNS records the results in the subfolder wcDNS\ with cached files per DNS request done by various parts of Wildcat! with DNS query needs.

With the introduction of wcDKIM, which is highly dependent on DNS queries, caching DNS query results was necessary for optimal performance and it was a drastic performance improvement overall for other parts of Wildcat! using DNS, such as WCSAP.

The cache folder wcDNS will grow with expire records. To maintain this collection, the console utility wcDNScache.exe is available to view the cache and pack (delete) expired records:

wcDnsCache v1.5 (c) copyright 2016 Santronics Software, Inc.
usage: wcdnscache [host] [options]

host           optional search domain

options:

List expired or non-expired:
  /l             list all files
  /le            list expired files
  /ln            list non-expired files
  /r             display records

Sort methods, use /xx- option for reverse order:
  /sn or /sn-    sort by file name
  /se or /se-    sort by file expire date (default)
  /sd or /sd-    sort by file date
  /sa or /sd-    sort by file age
  /sh or /sd-    sort by host name
  /st or /st-    sort by time to live (ttl)

Packing options:
  /pack          packed expired files
  /pack[:days]   start packing with optional days (default days = 7)

Other options:
  /cp:folder     set the cache folder (default: wcdns\)
  /rt:type       set the RR type, i.e. PTR, MX, PTR, A, TXT
  /? or /h       help
  /out:csv       output comma separated variable
  /dbg           debug

Examples:

  wcdnscache /l                  list files sorted by expire date
  wcdnscache /pack               pack all expired files
  wcdnscache /pack:2             pack all files 2 or days old
  wcdnscache /le                 list expirations
  wcdnscache /ln aol.com         list expirations for aol.com only
  wcdnscache /sa-                sort by age (oldest first)
  wcdnscache /st                 sort by ttl (low to high)
  wcdnscache aol.com /rt:mx /r   show mx records content for aol.com

Packing Example

wcDNSCache should be used on a regular event scheduled basis, daily, weekly or monthly depending on how the DNS queries load on your system. You can use wcTaskMgr or Windows Task Event Manager, for example to schedule an event calling a batch file with the commands:

    cd \wcat                <--- switch to your wildcat folder!
    wcDNScache /pack