Slyke Posted February 13, 2009 Report Share Posted February 13, 2009 I have 2 computers connected up to a 1GB switch.My Vista computer has a 1GB Ethernet NIC.My XP Computer has a 100MB/s Ethernet NIC.Since most of my movies and stuff are stored on the old XP computer I tend to stream them over the ethernet connection.This has been fine for the last year or so... Until a few days ago.Now when I try to stream a movie, it stops & starts & freezes.Also trading files has gone from about 10MB/s to about 5KB/s.Pinging works fine.I did however discover that:ping 192.168.1.20 -l 1472Reply from 192.168.1.20: bytes=1472 time=1ms TTL=128Reply from 192.168.1.20: bytes=1472 time<1ms TTL=128Reply from 192.168.1.20: bytes=1472 time<1ms TTL=128Reply from 192.168.1.20: bytes=1472 time<1ms TTL=128ping 192.168.1.20 -l 1473Request timed out.Request timed out.Request timed out.Request timed out.This is true for numbers larger then 1473 as well.I haven't changed any settings, haven't messed with any wires, or done anything.I installed VNC server, but it was working fine for a while (This all started about a week and a half after I installed it).I also tried changing it from auto to full 100 duplex - no effect.This is quite a mystery for me. Does anyone have any suggestions? Quote Link to comment Share on other sites More sharing options...
homecomputeraid Posted February 13, 2009 Report Share Posted February 13, 2009 Check the speed and duplex settings on both computers and set them manually. Set the Vista machine to Gigabit, and the XP machine to 100 mbps/Full Duplex. See if that helps. A speed or duplex mismatch could cause the symptoms, but I'm unsure why it would have such a definite size boundary.Another possible cause is that the mtu (maximum transmission unit) size has changed for some reason. Pretty strange. Any chance there's a virus or malware on one of the computers?http://www.speedguide.net/read_articles.php?id=157http://support.microsoft.com/kb/826159Microsoft Windows XP use a fixed MTU size of 1500 bytes for all PPP connections and use a fixed MTU size of 1400 bytes for all VPN connections.Of course, make sure both computers have all Windows Updates, and up to date antivirus and antimalware installed.You can try running netstat at the command line, or download tcpview to try to watch network activity:http://technet.microsoft.com/en-us/sysinte...92acd2c271.aspxIf you want to sniff actual network traffic, you can try WireShark:http://www.wireshark.org/download.html Quote Link to comment Share on other sites More sharing options...
Slyke Posted February 17, 2009 Author Report Share Posted February 17, 2009 Yep, everything's up to date. Changing the MTU didn't fix anything. Didn't even change the weird ping problem.They both have Firewalls installed, but I've even disabled them and it still does this.I'm about to check out the packet sniffer.I'm totally lost as to why this is happening. Quote Link to comment Share on other sites More sharing options...
Slyke Posted February 17, 2009 Author Report Share Posted February 17, 2009 Checked it out.Wireshark receives the echo request when sending 1473 bytes, but my computer doesn't reply? It replies when 1472 bytes are sent however.I tried this offline too (IE, net is disconnected). What should I set the MTU to?Don't know how this happened, or why, or how to fix! :(. Quote Link to comment Share on other sites More sharing options...
homecomputeraid Posted February 18, 2009 Report Share Posted February 18, 2009 What should I set the MTU to?What is it presently set at? If it's already bigger than 1473 bytes, it cannot be the problem. If it's lower than that, set it to 1500 and re-try the pings with the larger packet sizes.You could also try manually setting Vista to 100 mb full duplex and see if that helps anything. Quote Link to comment Share on other sites More sharing options...
Vik Posted February 19, 2009 Report Share Posted February 19, 2009 don't you think that it's all because of your provider? Quote Link to comment Share on other sites More sharing options...
catgate Posted February 19, 2009 Report Share Posted February 19, 2009 Are either of your machines a bit too warm? Quote Link to comment Share on other sites More sharing options...
Slyke Posted February 19, 2009 Author Report Share Posted February 19, 2009 It didn't have a default MTU in there.No Vik, it can't be my provider because it's all internal.You maybe right catgate, however it does it all the time, even after a cold reboot (It's had a cool down time of about 40 minutes, unplugged).The RPCSS service takes a while to startup I've noticed on reboots.I created a DWORD value at HKLM/SYSTEM\CurrentControlSet\Services\Tcpip\Parameters and set it to 5DCh, didn't fix the ping problem. I also tried a few of the tutorials above (Pretty much creating registry values in different places, mainly near HKLM/SYSTEM\CurrentControlSet\Services).I think a backup and format is in order personally. Quote Link to comment Share on other sites More sharing options...
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