Hi, I've setup IP Filter 3.2.10 on SCO OpenServer 5 to do NAT only. On NAT'ed workstations dns, http, ftp, smtp, pop3, telnet and chat work absolutely fine, except that a weird thing happens when downloading files from the internet or even from our ISP, be it via http or ftp. The problem is that downloads time out, and almost never a file larger than 2 Mb. can successfully be downloaded. I noticed the problem arises mainly during *mild* network congestion, that is, it seems as if downloads through the NAT server are not resilient to a slightly lower throughput and time out easily. I claimed the ISP but, after performing some throughput tests, they came to the conclusion that everything is OK with their service, and that possibly the problem is with my NAT implementation. As a matter of fact, I also performed some tests from within the server itself and *never* experienced the above-mentioned timeouts which derive in aborted downloads on the natted workstations. Another anomaly I consider worth mentioning is that downloads not only get aborted during the file transfer, but also before transfer starts. For example, when the guy on any workstation clicks a link on his internet explorer to download a file, and then he takes more than, say, 15 seconds to locate the destination folder on his machine, Internet Explorer (and Netscape alike) issue the message that there is a network error to reach the web server and the transfer gets aborted *before* starting. For this to not occur, the user must quickly initiate the transfer and save the file to whatever folder IE points too. Anyway, the transfer will surely time out at a later time and get aborted.
I'm not sure if ipfilter is responsible for this situation, but I will highly appreciate if someone from the list that knows a workaround for it lets me know how to fix it. My NAT rules are few and simple: map net0 0.0.0.0/0 -> 0/32 proxy port ftp ftp/tcp map net0 192.168.1.0/24 -> 0/32 proxy port ftp ftp/tcp map net0 192.168.1.0/24 -> 0/32 portmap tcp/udp 10000:40000 map net0 192.168.1.0/24 -> 0/32 They're in the file /etc/ipnatrules and are invoked with the following command line: "ipnat -vf /etc/ipnatrules" By the way, net0 is the public network interface which has a static, public IP address and 192.168.1.x are the private IP addresses manually assigned to the workstations on the LAN. Also, there are no download accelerators of any sort installed and the IP address bound to the public interface is not behind any proxies or natted on the ISP side. Thank you, Fernando Ronci E-mail: [EMAIL PROTECTED]
