There might be several reasons. First check that SageMath is really
running:
ps afx | egrep -i [s]age
then, what was the exact command for notebook()? Assuming you used port
22334, try
fuser -n tcp 22334
or
netstat | fgrep 22334
and last, is there a hole in the firewall? Try
iptables -L | fgrep 22334
assuming you have a firewall set up.
--
Jori Mäntysalo
Tampereen yliopisto - Ihminen ratkaisee