Hi. On Mon, Sep 18, 2017 at 07:48:53PM +0100, Brian wrote: > On Mon 18 Sep 2017 at 20:13:44 +0200, deloptes wrote: > > > Reco wrote: > > > > > The question is - since 'localhost.localdomain' is special, what happens > > > if such hostname is chosen during the installation? > > > > well, now we all know what happens :) > > True, we know the OP has a problem with with sudo.
That's what lie on surface. Any software that implements uname/gethostbyname sequence would exhibit similar behavior. > What we do not know > is the hostname he chose during the installation, although it looks like > it was "localhost" from the second line of > > 127.0.0.1 localhost > > 127.0.1.1 localhost I agree. > The installer recommends a single word for the hostname. The "single" > aspect is the result of a number of years of experience and bug reports. And let's not forget RFC 952 (obsoleted by RFC 1123), which states: A "name" (Net, Host, Gateway, or Domain name) is a text string up to 24 characters drawn from the alphabet (A-Z), digits (0-9), minus sign (-), and period (.). Note that periods are only allowed when they serve to delimit components of "domain style names". RFC 1123 lifts some restrictions: One aspect of host name syntax is hereby changed: the restriction on the first character is relaxed to allow either a letter or a digit. Host software MUST support this more liberal syntax. Host software MUST handle host names of up to 63 characters and SHOULD handle host names of up to 255 characters. But does not says anything about dots, so restrictions of RFC 952 still apply. > Although "localhost.localdomain" is not an invalid hostname I agree as long as 'invalid' is defined as 'kernel does not accept it'. For instance, one can set nodename as 'localhost.local' and watch avahi explode. Or, say, '_localhost', if one intends to wreak havoc in local DNS's SRV records. The kernel is surprisingly liberal at these things. > the OP does not appear to have used it. (We have not been given the > contents of his /etc/hostname explicitly). True. We also did not see the contents of sysctl.conf (and those *other* files that can store kernel tunables), custom init.d scripts and custom systemd units if there were any. To make things more confusing, 'localhost.localdomain' could be a 'transient' hostname, not a 'static' one (aka /etc/hostname). It's one of those things I prefer to debug with auditd on. Too many possibilities otherwise. > What was the problem with his resolv.conf? Have I missed that? OP used an unspecified VPN client which put an additional entry into /etc/resolv.conf on start, but failed to clean it up on stop. Reco
