Hi, On 2014-09-02 23:03:50 +0200, Joachim Breitner wrote: > Am Dienstag, den 02.09.2014, 18:33 +0200 schrieb Vincent Lefevre: > > I had "files" first in "hosts:" (I suppose that this corresponds > > to /etc/hosts), and still first after libnss-myhostname got > > installed. This means that libnss-myhostname overrode it. But > > I'll try to look what is done with strace. > > not sure what you mean. libnss-myhostname currently installs itself > always directly after files.
I meant that I have hosts: files mdns4_minimal [NOTFOUND=return] dns mdns4 without libnss-myhostname, and hosts: files myhostname mdns4_minimal [NOTFOUND=return] dns mdns4 with libnss-myhostname. In both cases, "files" has the precedence over everything else, and the FQDN can be obtained from /etc/hosts, so that it is strange that libnss-myhostname changes the behavior. See below for the explanation. > > What does "Existing installations are not modified." mean? I ask this > > because /etc/nsswitch.conf got modified. > > Existing installations of libnss-myhostname, i.e. if it is already > present in /etc/nsswitch.conf. What if libnss-myhostname is installed but the user has removed "myhostname" from /etc/nsswitch.conf? > If you move it to the end of the line there, does it work better for > you? No, same problem with: hosts: files mdns4_minimal [NOTFOUND=return] dns mdns4 myhostname With "strace -o strace.out exim4 -bP", I can see that /etc/hosts is read, but I don't know whether this is meaningful. Exim does the following: it first calls gethostbyname2(nodename, AF_INET6) and if it returns NULL, it calls gethostbyname2(nodename, AF_INET) When myhostname is not used, the first call (with AF_INET6) fails (because in /etc/hosts, only IPv4 is set up as this is sufficient locally), and the second call returns the FQDN ypig.lip.ens-lyon.fr. When myhostname is used, the first call succeeds, but once just gets ypig. So, the problem seems to be that myhostname adds a host for IPv6, overriding the IPv4 user's /etc/hosts setting when IPv6 is tried first. IMHO, before changing anything, libnss-myhostname should first detect whether the nodename is resolvable with either IPv4 or IPv6 (checking for IPv4 only should be sufficient in practice, but this might change in a distant future once IPv4 has disappeared). If it is, then it should not change anything. -- Vincent Lefèvre <vinc...@vinc17.net> - Web: <https://www.vinc17.net/> 100% accessible validated (X)HTML - Blog: <https://www.vinc17.net/blog/> Work: CR INRIA - computer arithmetic / AriC project (LIP, ENS-Lyon) -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org
