Sick network routing question.

It all starts with the Atari. Here's a quick rundown of what is connected to what etc. Machines: Serial Leg: Atari MegaST4 - Running MiNT (a BSD unix flavor): (AtariST) 192.168.1.2 PPP link via ttya@19200bps -----> (Sparcstation) running OpenBSD v3.2: (Sparc) ttya 192.168.1.1 ----> BNC Ethernet Leg: (Sparcstation) (same machine as host for ppplink)) Ethernet link le0 192.168.1.39 ----> (Benchbox) Win2k Default gateway (Win2k NAT) 192.168.1.55 -----> Cat 5 Leg: 2nd nic in win2k Nat router. This one Natted 192.168.0.1 ---> (NoHostName) Linksys NAT router: 192.168.0.254 ---> Nat routed internet. Not having a hub with a BNC port on it has forced me to use a BNC nic in one of the machines to provide a bridge. I used NAT because I am too stupid to use something other than NAT. I could connect the Atari to the Win2k machine via ppp and get a connection, but the machines on the BNC and serial leg are a floor below the machine acting as the router for that leg. I don't want to run a 40" serial cable next to the BNC cable run just so the ST can surf.... Especially since: I suspect I'm missing something fantasticly simple and that the problem I face with the Win2k machine and the problem with the Atari on the Sparc are likely going to be solved the same way. How? Please? Bonus question.... Has anyone ever 'shotgunned' two serial ppp connections to one ip so as to double throughput? Is this a gawdaweful mess or can I use something like this to speed up the link to the ST? I can't go faster than 19.2k reliably so another connection is the only way. I am seriously thinking about an Ne2000 for the ST, but haven't even started building that. (Notes really. The meat is above.) The main problem I'd like to solve is on the Sparc. I'm not sure I understand what needs to be done here. I don't want to use ANOTHER nat router on the Sparc. I know that works, but I'd like to get rid of any extra Natting period which includes the one running on Benchbox. What do I need? Gated? Routed? I think I'm a little lost. I've done this for wans using Cisco and Ascend routers, but the software approach is kicking my butt a bit. I've used OS/2, Linux, NetBSD, OpenBSD, and Windows-based Nat routers in this configuration so the problems with FTP below are the same if I chose to use them as the router for that 'leg' of the network. FTP connections from machines behind the 2nd nat router are flaky with FTP downloads. They are all going through two nat routers so I can understand there might be a problem with passive ftp, but why? So I can at least understand if not fix. Thanks for entertaining my question and I hope one of you has the kindness help even though this isn't exactly a purely topical posting. Regards, Jeff