Forum Moderators: bakedjake
However, some ICMP packets may be needed for proper network routing. (These would be generated by the protocol stack on the Linux system, or by your default router - or at least *a* router, not directly by the FTP server.) I'd check your firewall settings to make sure that ICMP is allowed.
How is your network subnetted? You might want to double-check this. If the virtual systems are on separate subnets, try setting an explicit route from each system to the other - i.e. to avoid going through your default router, which would then send an ICMP redirect, which might be blocked by one or the other firewall.