Unless you disable DNS lookups altogether with the -n option, ping performs a DNS lookup every time it sends an ICMP echo. This is distinctly anti-social behaviour, especially considering that the only reason it does a DNS lookup is to make the output prettier. This behaviour doesn't seem to occur with Redhat 6.0 and 6.1, presumably because their ping comes from netkit-base rather than from iputils. For reference, the maintainer of iputils seems to be <kuznet.ac.ru>, so I guess he should be contacted about this.
No kidding. If I give a numeric IP address to ping I don't expect it to request and require DNS reverse IPaddr-to-name entries to work. Geez. I just wasted an hour trying to figure out what was introducing a large random number of seconds delay when I did "ping 10.100.58.140" and didn't use the "-n" option. I've been using ping for 20 years and never had to use the "-n" option for this basic diagnostic tool to work before. Please FIX. thanks. nn
An hour? I just lost five days to this "feature". DNS at my work changed without notice, and I've been fighting ever since trying to figure out why *all* my connectivity just stopped working. tcpdump didn't turn up the dns queries, or I might have noted it sooner.
*** This bug has been marked as a duplicate of 10436 ***