A new *DNS_CACHE* module has been added to OpenSIPS trunk, and it will
also be present in the future 1.8 release.
In the current OpenSIPS design, I/O Operations, DNS included, are done
in a blocking way, with the SIP workers having to wait for the DNS query
to return, until further processing can be done. Slow DNS servers are
often a source of performance degradation, and DNS queries that are not
resolvable have an even larger performance impact.
The new *DNS_CACHE* module implements the Key-Value Interface  to
allow caching of DNS records in a user-chosen back-end ( local cache,
memcached, etc. ) for the TTL number of seconds returned in the DNS
response, thus greatly improving the speed of subsequent DNS requests
for the same domain. Failed queries ( without any records found in DNS )
are also cached with a user-chosen duration.
For a full documentation of the module, visit  .
Testing and feedback is very much welcomed.