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nsping.8
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.Dd October 1997
.Dt NSPING 8
.Os BSD 4.4
.Sh NAME
.Nm nsping
.Nd measure reachability and latency of DNS nameservers
.Sh SYNOPSIS
.Nm nsping
.Op Fl drR
.Op Fl c Ar count
.Op Fl z Ar zone
.Op Fl h Ar hostname
.Op Fl t Ar timer
.Op Fl p Ar port
.Op Fl P Ar port
.Op Fl a Ar address
.Op Fl T Ar type
.br
.Op <address>
.Sh DESCRIPTION
.Nm Nsping
uses DNS queries to monitor reachability and operation of nameservers,
as well as the latency of DNS queries. It does this by sending random
recursive DNS queries to the nameserver (avoiding the effects of
DNS caching) and measuring the amount of time between the sending
of the query and the receipt of the response packet.
.Pp
The latency of DNS transactions depends heavily on the data being
queried for. The zone within which to query can be specified explicitly
on the command line, or inferred from the local host. To measure
the responsiveness of a nameserver for information it is authoritative
for, specify one it's zones of authority as this zone.
.Pp
To measure basic network latency and DNS processing time, specify
a hostname on the command line. If this is done, DNS queries sent
by
.Nm nsping
will not be randomized, and nameservice caching will cause the program
to measure only network+processing time. If latency between the
first and subsequent queries does not vary greatly, nameservice caching
may not be enabled on the probed server.
.Pp
Finally, a rough estimate of the latency between two sets of nameservers
can be measured by querying one of those servers for information within
a zone authoritative for the other servers. This would be more useful
if there was a way to specify which of a zone's servers a target server
queries.
.Pp
.Nm Nsping
recognizes the following options:
.Bl -tag -width "-ac"
.It Fl c Ar count
Total number of DNS queries to send (default infinite).
.It Fl z Ar zone
The DNS domain to formulate queries in.
.It Fl h Ar hostname
Do not use random queries, but rather query repeatedly for one
hostname.
.It Fl t Ar timespec
Specify the interval timeout to send packets with, as an
expression of seconds.subseconds (ie, 0.5 = half second).
(default 1 second).
.It Fl p Ar port
The remote DNS server port.
.It Fl P Ar port
The local port to send queries from
.It Fl a Ar address
The local address from which to send queries.
.It Fl T Ar type
The type of information
to query for (default "a" for Internet "A" record).
.It Fl d
Print debugging output (don't do this).
.It Fl r
(Redundant) use recursive queries.
.It Fl R
Don't use recursive queries.
.El
.Sh EXAMPLES
.Bl -tag -width apply -compacy
.It Li "nsping ns.victim.com"
Ping the nameserver "ns.victim.com" until interrupted using
defaults (random queries, local domain name as zone, etc).
.It Li "nsping -z internic.net -t .5 ns.victim.com"
As above, but query for names within the domain "internic.net",
and do so every half-second instead of every second.
.It Li "nsping -h www.yahoo.com ns.victim.com"
Query repeatedly for "www.yahoo.com" from ns.victim.com.
.El
.Sh AUTHOR
Thomas H. Ptacek, <tqbf@secnet.com>
.Sh BUGS
This is embryonic software. If you find a bug, let me know;
I won't be surprised, but I will try to fix it for you. =)
.Sh HISTORY
Real benchmarking tools can be found at WWW.CAIDA.ORG; this
tool is merely inspired from them.