Optimal MTU size for Router Settings in Partial loss of internet connection
General instruction for finding your optimal MTU size Go to Start and select Run. Set router to MTU 1500 to start with. Start RUN Type in cmd (Windows 2000/XP/Vista/7) or command (Windows 98/ME) into the box . Hit the enter key or click OK At the DOS prompt, type in ping bbc.co.uk -f -l 1492 and hit the Enter key. If you get the response "Packet needs to be fragmented but DF set", lower the size the packet in increments of +/-10 (e.g. 1472, 1462, 1440, 1400) until you have a packet size that does not fragment. Now increase the packet size from this number in small increments until you find the largest size that does not fragment. Add 28 to that number (IP/ICMP headers) to get the optimal MTU setting. For example, if the largest packet size from ping tests is 1462, add 28 to 1462 to get a total of 1490 which is the optimal MTU setting and can be put in your router's settings! Hope this helps some of you!? Source : NETGEAR site.