Re: Problem in getting local IP through
Re: Problem in getting local IP through
- Subject: Re: Problem in getting local IP through
- From: "Justin C. Walker" <email@hidden>
- Date: Tue, 24 Jun 2003 22:31:16 -0700
On Tuesday, June 24, 2003, at 09:51 PM, Pranav Kumar Sahu wrote:
Actually i am using "gethostbyname()" to get the hostent and then I am
converting it to a in_addr. Where I have the problem with the IP
Address.
Since it returns proper IP Address in some systems and "127.0.0.1" in
few
system, I feel I need to configure some network setting.
"127.0.0.1" is a proper IP address. As Josh indicated, you are getting
a *list* of addresses, and you have to look at each in the list
(h_addr_list).
The problem you are having may be that you want a single IP address,
and there really is no such thing in today's IP world. Each system can
have multiple active interfaces (e.g., "lo0" for loopback; the built-in
ethernet adapter; and an airport/wireless adapter); and each interface
can have multiple valid IP addresses, some of which will have global
scope, and some of which won't (the latter can be RFC 1918 "private"
addresses, or "zero-conf/link-local" addresses). This situation will
only "improve" as IPv6 gains currency, so developers need to learn to
deal with it.
Since there will be (potentially) many IP addresses assigned to your
host, trying to specify "the" IP address is not going to work well.
Looking at Quinn's opus on this subject (TN1145 - Living in a Dynamic
TCP/IP Environment) may help.
In your case, it appears that the given host name is set up to refer
both to the loopback address (127.0.0.1) and another address, but it's
hard to tell without more details. What are you trying to achieve?
Regards,
Justin
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