NAT warning if IPv4 loopback address in /etc/resolv.conf

2019-04-04 16:40:04 -07:00
parent 598d694058
commit 664ba39383
1 changed files with 4 additions and 0 deletions
@@ -388,6 +388,10 @@ class MininetRunner( object ):
                  listenPort=opts.listenport )

        if opts.ensure_value( 'nat', False ):
+            with open( '/etc/resolv.conf' ) as f:
+                if 'nameserver 127.' in f.read():
+                    warn( '*** Warning: loopback address in /etc/resolv.conf '
+                          'may break host DNS over NAT\n')
            mn.addNAT( *opts.nat_args, **opts.nat_kwargs ).configDefault()

        # --custom files can set CLI or change mininet.cli.CLI