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Subject: FreeTDS Development Group
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- From: "Jackson, Craig (Gale)" <Craig.Jackson AT cengage.com>
- To: FreeTDS Development Group <freetds AT lists.ibiblio.org>
- Subject: Re: [freetds] connect(2) for UDP
- Date: Mon, 15 Dec 2008 23:52:54 -0500
> I got the idea from Chapter 8.11 of Stevens's "Unix Network Programming",
> Volume 1, 3rd edition, page 252. And he says what you said:
>
> "[T]he kernel just checks for any immediate errors ... records the IP
> address and port number of the peer ... and returns immediately to the
> calling process."
Yep. For UDP, having the other end not be listening is not an immediate
error.
> The same program, when trying to communicate with a down host, times out
> reading. Not surprising, on reflection, because there's no machine to
> send that ICMP message.
Note that some last-hop routers will make an ICMP Host Unreachable response
on a down host, because the ARP fails. I don't know if this will be turned
into a useful diagnostic by the UDP layer. In any case, it takes some time
for it to decide if the ARP has timed out.
Craig
-
[freetds] connect(2) for UDP,
James K. Lowden, 12/15/2008
-
Re: [freetds] connect(2) for UDP,
Jackson, Craig (Gale), 12/15/2008
-
Re: [freetds] connect(2) for UDP,
James K. Lowden, 12/15/2008
- Re: [freetds] connect(2) for UDP, Jackson, Craig (Gale), 12/15/2008
-
Re: [freetds] connect(2) for UDP,
James K. Lowden, 12/15/2008
-
Re: [freetds] connect(2) for UDP,
Frediano Ziglio, 12/17/2008
-
Re: [freetds] connect(2) for UDP,
James K. Lowden, 12/17/2008
-
Re: [freetds] connect(2) for UDP,
Peter Deacon, 12/17/2008
-
Re: [freetds] connect(2) for UDP,
Peter Deacon, 12/18/2008
- Re: [freetds] connect(2) for UDP, Frediano Ziglio, 12/18/2008
- Re: [freetds] connect(2) for UDP, Jackson, Craig (Gale), 12/18/2008
- Re: [freetds] connect(2) for UDP, James K. Lowden, 12/18/2008
-
Re: [freetds] connect(2) for UDP,
Christos Zoulas, 12/18/2008
-
Re: [freetds] connect(2) for UDP,
James K. Lowden, 12/18/2008
- Re: [freetds] connect(2) for UDP, Christos Zoulas, 12/18/2008
-
Re: [freetds] connect(2) for UDP,
James K. Lowden, 12/18/2008
-
Re: [freetds] connect(2) for UDP,
Peter Deacon, 12/18/2008
-
Re: [freetds] connect(2) for UDP,
Peter Deacon, 12/17/2008
-
Re: [freetds] connect(2) for UDP,
James K. Lowden, 12/17/2008
-
Re: [freetds] connect(2) for UDP,
Jackson, Craig (Gale), 12/15/2008
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