described in RFC 1788, I wrote a simple implementation in user-space.
It comprises three parts:
- * icmpdnd – The ICMP Domain Name daemon, which listens to ICMP
+ * icmpdnd - The ICMP Domain Name daemon, which listens to ICMP
domain name requests and replies to them.
- * idnlookup – A user utility to query a host for its host name over
+ * idnlookup - A user utility to query a host for its host name over
ICMP. Like ping and all other utilities that use ICMP, it needs to
be installed SUID root.
- * libnss_icmp.so.2 – A glibc NSS module, which uses idnlookup to
+ * libnss_icmp.so.2 - A glibc NSS module, which uses idnlookup to
perform queries for the gethostbyaddr function.
General information
TTL value sent by the responding host. It uses a configuration file called
/etc/nss-icmp.conf, which controls different aspects of its operation:
- * timeout – Sets the timeout in milliseconds for ICMP host name
+ * timeout - Sets the timeout in milliseconds for ICMP host name
queries, by passing the -t option to idnlookup.
- * nocache – Disables the cache.
- * ttlnotfound – Sets the TTL for not-found cache entries is
+ * nocache - Disables the cache.
+ * ttlnotfound - Sets the TTL for not-found cache entries is
seconds. The default is 5 minutes.
Both icmpdnd and idnlookup need to run as root, due to the fact that