For anyone using FC4, it seems that JDK 1.4 is unable to make any network connections due to IPV6 being enabled in the kernel - 1.5.0_03 works fine.



Fortunately, disabling IPV6 seems to fix it (reboot needed).


/etc/modprobe.conf:
# Disable IPV6 to allow java networking to work
alias net-pf-10 off