On May 23, 2008, "Colin Walters" <walters@xxxxxxxxxx> wrote: > On Thu, May 22, 2008 at 11:47 PM, Matthew Miller <mattdm@xxxxxxxxxx> wrote: >> >> But "is the network up" a generally useful question? > Yes. > --Colin, who just finished last night implementing much improved > network status handling in his SSH client via NetworkManager > http://svn.gnome.org/viewvc/hotwire-ssh/trunk/hotssh/sshwindow.py?limit_changes=100&r1=4&r2=5&pathrev=5 So what does it do when one out of 3 networks a server is directly connected to is down, and you attempt to connect to a host that is reachable through one of the working interfaces? How does "is the network up?" even being to make sense for anything with more than one network interface? What if two of the networks have redundant paths out to the Internet, and the third doesn't, and only the third is up at a given moment? And what if you're not trying to reach the Internet, just another server down the hall that *is* reachable? Heck, what if I'm just trying to reach one of the virtual machines running on the local server, while the primary network interface was taken off line? What if I'm trying to diagnose a firewall problem on my server that makes it *look* like the network is down for whatever heuristics NetworkManager uses to make its decision, but that lets enough through that I could get in from my desktop? And vice-versa, except that I'm not allowed to connect to my desktop because the network is allegedly down. How do you even begin to define 'network', to be able to decide what the 'up' is about? I don't doubt it's possible to make up a number of examples in which the question actually makes sense and it has an answer that also makes sense, but that's hardly enough to extend the claim from "useful for some relevant cases" to "generally useful". I think we're still quite distant from the DWIM pipe dream. -- Alexandre Oliva http://www.lsd.ic.unicamp.br/~oliva/ Free Software Evangelist oliva@{lsd.ic.unicamp.br, gnu.org} FSFLA Board Member ¡Sé Libre! => http://www.fsfla.org/ Red Hat Compiler Engineer aoliva@{redhat.com, gcc.gnu.org} -- fedora-devel-list mailing list fedora-devel-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/fedora-devel-list
