CentOS 7.3 Mozilla Firefox 52.2.0 (64) Web Server and framework : Django Firefox is showing 'undefined' error randomly (once in 20-30 attempts) while acquiring IP for bridge network interface using 'dhclient' . The sequence of command is, tunctl -t tap0 -u `id -un` -g `id -gn` brctl addbr $bridge ifconfig tap0 up brctl addif $bridge tap0 ifdown ens160 ifconfig ens160 0.0.0.0 promisc up brctl addif $bridge ens160 ifconfig $bridge hw ether xx:xx:xx:xx:xx:xx dhclient -r $bridge dhclient $bridge ifconfig $bridge up

Web server is giving 'Broken Pipe' error. This issue cannot reproduce in other browsers. The entire setup is running in Vsphere-VM. The same issue reproduced with Apache webserver also. In the broken pipe cases dhclient is taking more time.