#1:
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Please post the output of
$ route -n show -inet
You may redact any private information, such as your Internet IP address.
I ask for your routing information, because you just stated that you have a mygate(1) file, containing incorrect information ("192.168.1.1"). Your default route should be assigned by your ISP. If your ISP connection uses DHCP, the default route will be added when you connect. If your ISP connection is static, your ISP should have provided this information.
/etc/mygate is used for
static ip address configurations, and describes the default route. Perhaps, if you are using DHCP, a default route is already correctly added, then the use of an incorrect /etc/mygate just causes an error when /etc/netstart issues the route add for it. (That error should appear in /var/log/messages with each boot; you may want to look for it.)
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#2
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Run tcpdump against your internal wired network, to see if the incoming Sync packet from the Internet makes it onto the local LAN. Perhaps the source of your problem is the server at 192.168.0.10. If you see packets get sent to the server, but no valid responses, you have a server problem. If you see valid two-way traffic back and forth, then run tcpdump against your external network. On the external network, if you only see the incoming packet, but no outbound responses, you have a routing problem.
e.g.:
# tcpdump -neti re0 host 192.168.0.10
# tcpdump -neti em0 host <your remote workstation>