1. System Ping (to resolve DNS)
Hi folks
As part of an Internet client/server set of apps that I'm working on,
I'm including a function to resolve the domain name to the associated
IP. (btw, I'm using win32lib and eulibnet includes at the moment.)
The way I've done it (certainly not the easiest, but it's the only way I
could easily figure to do it) is to call the system's PING command
(i.e., system("ping domain.com > pingresult.txt", i) - and can't
remember whether I'm using 1, 2, or 3 as "i", but doesn't matter).
Then I open this pingresult.txt file for reading within my program, and
get the IP from the second line, which is between the "[" and "]". Kind
of kludgy (sp?), but it works.
What I don't like, other than the obvious kludginess of the coding to do
all this, is that it opens a console window when it calls the system
command -- not very elegant when the rest of the program is a
nice-looking (IMHO) window.
>From the documentation, I 'think' system_exec() doesn't open a console,
but it also says that re-direction cannot be used. I'd have to test it
of course, but...
Surely there's a more elegant way to do Internet resolution of domain
names. Do any of you know something that'll work entirely within the
windows program (i.e., no additional console), and might be something as
simple as:
include dns.e
sequence IPaddress
dns_resolve(domain.com)
IPaddress = whatIsReturnedFromdns_resolve
As mentioned, I'm using eulibnet, but I don't see anything in there that
might do it (although I haven't fully inspected eulibnet.ew) -- perhaps
there's something in tcp4u.ew?
Thanks in advance folks.
Mark.
2. Re: System Ping (to resolve DNS)
On 30 Jul 2002, at 18:35, Mark Moran wrote:
>
> Hi folks
>
> As part of an Internet client/server set of apps that I'm working on,
> I'm including a function to resolve the domain name to the associated
> IP. (btw, I'm using win32lib and eulibnet includes at the moment.)
>
> The way I've done it (certainly not the easiest, but it's the only way I
> could easily figure to do it) is to call the system's PING command
> (i.e., system("ping domain.com > pingresult.txt", i) - and can't
> remember whether I'm using 1, 2, or 3 as "i", but doesn't matter).
>
> Then I open this pingresult.txt file for reading within my program, and
> get the IP from the second line, which is between the "[" and "]". Kind
> of kludgy (sp?), but it works.
>
> What I don't like, other than the obvious kludginess of the coding to do
> all this, is that it opens a console window when it calls the system
> command -- not very elegant when the rest of the program is a
> nice-looking (IMHO) window.
>
> >From the documentation, I 'think' system_exec() doesn't open a console,
> but it also says that re-direction cannot be used. I'd have to test it
> of course, but...
>
> Surely there's a more elegant way to do Internet resolution of domain
> names. Do any of you know something that'll work entirely within the
> windows program (i.e., no additional console), and might be something as
> simple as:
>
> include dns.e
> sequence IPaddress
> dns_resolve(domain.com)
> IPaddress = whatIsReturnedFromdns_resolve
>
> As mentioned, I'm using eulibnet, but I don't see anything in there that
> might do it (although I haven't fully inspected eulibnet.ew) -- perhaps
> there's something in tcp4u.ew?
No, but i have that on my to-do list also. Here is some possibly useful info:
look for "gethostbyaddr" in:
winsock.ew or ExWinsock.ew
ftp://ftp.stardust.com/pub/winsock/version1/docs/spec/winsock.html
http://www.ibiblio.org/winsock/winsock-1.1/winsock.html
The call is in the tcp4w32.dll, so it is prolly accessable somewhere.
ICMP 37= Domain Name Request
ICMP 38= Domain Name Reply
CNAME
The {canonical name} query type for {Domain Name System}.
This query asks a DNS {server} for a {host}'s official
{hostname}.
( it's case-insensitive )
see also:
RFC 1034
RFC 1035
I use the nameserver at 216.136.133.88.
Kat
3. Re: System Ping (to resolve DNS)
Actually, if you go to http://pages.prodigy.net/mirwalds/ you will find
tcp.ew on the page. It includes heaps.e and structs.e (both by Chris
Bensler) to handle the memory operations, but it wraps the Async versions of
both gethostbyname() and gethostbyaddr().
It does handle alot of the painfull stuff for Async lookups, and I believe
that the libs are all compatable with win32lib.
The zip file itself is here: http://pages.prodigy.net/mirwalds/tcp.zip
Jason
4. Re: System Ping (to resolve DNS)
Hi,
Probably best to do this via winsock, you could use one of the winsock
wrappers available but if all you need is the DNS resolve then have a
look at this bit of code I posted a while ago:
http://www.rat-software.com/misc.html
Thomas Parslow (PatRat)
E-Mail/Jabber: tom at almostobsolete.net
ICQ: 26359483
