On Fri 24 May 2024 at 13:40:38 (-0400), Jeffrey Walton wrote: > On Fri, May 24, 2024 at 11:13 AM Paul M Foster <pa...@quillandmouse.com> > wrote: > > > > Folks: > > > > In my /etc/hosts file, there's a line: > > > > 127.0.1.1 yosemite.mars.lan yosemite > > > > I think Debian put it there. > > > > Later in the file, I've got: > > > > 192.168.254.30 yosemite.mars.lan yosemite > > > > So there are two entries for the same (my) machine. Is this a problem? > > Specifically, could it cause problems with email (Exim4 or OpenSMTPD)? > > 127.0.1.1 is traditionally used for the fully qualified domain name > (fqdn). So I would expect to see 'yosemite.mars.lan', but not > 'yosemite'. > > Also, fqdn's end in dot '.' to denote the top of the dns tree. So I > would expect to see 'yosemite.mars.lan.' (note the trailing dot), and > not 'yosemite.mars.lan' (note the lack of the trailing dot). What can > happen with 'yosemite.mars.lan' is, search domains can be added to it. > So if dhcp says 'isp.com' is a search domain, then your network stack > might make requests for 'yosemite.mars.lan.isp.com'.
You must have a very unusual hosts file then, on both those counts. I would expect just the 127.0.1.1 line as written, and I'm going to guess that the 192.168.254.30 line was added as a misguided attempt to get LAN mail working. As noted by others, /etc/hosts is not the correct place for that. Cheers, David.
