asp - find an host IP
address by its name
| [-d dir
]] [-a addresses
] [-r repetitions
] [-w wait_time
finds the IP
address of an Internet connected host. In
order to find it, the peer hostname
(not the FQDN), and the range of
its possible IP
addresses need to be specified. Those
addresses could be simple IP
127.0.0.1 or "metaip" addresses as 127.0.0.1-20 or 127.0.0.*: the
former is a simple way to avoid to type a lot of consecutive addresses, the
latter is short for 127.0.0.1-254.
In order to simplify the management of the associations between hostnames and
searches in a specified directory a text file containing
the possible IP
addresses of the looked for host. The name of
the text file has to be formed by the hostname
followed by an optional
extension of your choice.
For example to find the author's dynamic IP
address, obviously if
I am on line, you can provide my metaip address on standard input with the
126.96.36.199-18" | asp -f atomic
or you can put my metaip address in a file called atomic
directory, like this:
188.8.131.52-18" > ~/.asp/atomic
and then you can simply do:
- Update the file /etc/hosts with the
IP address of hostname or delete the possible old
entry if the address is not found. Obviously the file have to by writable
by the user.
- Include more verbiage to make output readable by humans.
Default consists only of dotted quad IP address, which is
intended for output substitution in scripts.
- Force the reading of addresses from standard input instead
that from the hostname's file.
- -d dir
Set the directory containing the addresses file referred by hostname
to dir. Default is ~/.asp.
- -e ext
Set addresses files extension to ext. Default is no extension.
- -a addresses
Set the number of queries to send before make a pause of send_delay
seconds. Default is 12 queries.
- -r repetitions
Set the number of times to try the same address. Default is 3 times.
- -s send_delay
Delay the sending of the next group of addresses send_delay
seconds. Default is 2 seconds.
- -w wait_time
Wait the peer reply for wait_time seconds. Default is 5 seconds.
- -p port
Specify an alternative port number. For default the port number is
obtained searching the asp entry in /etc/services.
- Show version information.
- This variable could be used to store your preferred
settings. An option set in this environment variable could be overridden
or toggled from command line.
is an unreliable protocol, therefore there is a chance you
will not find the host even if it is on line. Anyway, if you are sure that the
peer is on line and asp aware, you could adjust the various parameters until
you get a reply. At last you will find the correct settings for your
particular needs. This until the RDM
communication style will
be implemented under Linux.
Obviously the hostname
has to be unique among the possible
will hook to the first correct reply.
Stenio Brunetta <email@example.com>
Comments and suggestions are welcome.
Steven N. Hirsch <firstname.lastname@example.org> for v1.3 bug fix and for the verbose
Colin Phipps <email@example.com> for the tmpnam security issue.