CAN'T ACCESS SOME WEBSITES?
Does this happen to you? Every now and then when posting or previewing a post, or simply browsing; you get the page not available message or takes a long time to view? If you look at your firewall's log, you'll see that your ISP's and/or router IP is blocked (192.168.1.254 or .1).
1. Find the IP address of your gateway. If you're using Windows 2000 or XP, run IPCONFIG at a command prompt on the Host computer. If you're using Windows 98 or Me, run WINIPCFG on the Host computer. Either way, you'll get an address that looks like xxx.xxx.xxx.xxx (where the x's represent numbers).
a.) Then, go to one of your Client machines, and type the following:
b.) PING -f -l 1500 xxx.xxx.xxx.xxx
(where xxx.xxx.xxx.xxx is the gateway address you obtained in the first step). You'll probably get an error message indicating that it must be fragmented. If you do, type the following:
c.) PING -f -l 1492 xxx.xxx.xxx.xxx
If that doesn't work, try this:
d.) PING -f -l 1472 xxx.xxx.xxx.xxx
2. The numbers in each of these examples (1500, 1492, 1472) are the MTU values. Continue issuing this command with lower and lower MTU numbers until you get ping responses instead of an error message. The highest MTU value that works is the one you need to be using. If an MTU of 1500 (the first command, above) does not produce an error, then this solution won't work for you.
The next step is to configure all your Client computers to use the new, lower MTU as the default for all Internet communication.
Windows 2000 and XP:
1. Run the Registry Editor (REGEDIT.EXE) on one of your "Client" machines.
2. Navigate to HKEY_LOCAL_MACHINE\ SYSTEM\ CurrentControlSet\ Services\ Tcpip\ Parameters\ Interfaces
3. There should be several subkeys under the Interfaces key; most likely, you'll find three. View the contents of each key by clicking, and find the one that corresponds to your primary network adapter; it will be the one with more values than the other two, and will have an IP address value set to something like 192.168.0.x.
4. Once you've found the correct subkey, create a new DWORD value in it (Edit -> New -> DWORD Value), and name the value MTU.
5. Double-click the new value, choose the Decimal option, and type the MTU value determined above.
6. Click Ok when you're done - you'll need to restart Windows for this change take effect.
7. Repeat this for each Client machine.
Windows 98/Me:
1. Run the Registry Editor (REGEDIT.EXE) on one of your "Client" machines.
2. Navigate to HKEY_LOCAL_MACHINE\ System\ CurrentControlSet\ Services\ Class\ Net
3. Under that branch, find a key (numbered, such as 0005) that contains has TCP/IP assigned to the DriverDesc value.
4. Select New from the Edit menu, then String Value, and type MaxMTU for the name of the new value.
5. Double-click the new value, choose the Decimal option, and type the MTU value determined above.
6. Click Ok when you're done - you'll need to restart Windows for this change take effect.
7. Repeat this for each Client machine.
RESULTS WILL VARY
No matter how good your systems may be, they're only as effective as what you put into them.
1. Find the IP address of your gateway. If you're using Windows 2000 or XP, run IPCONFIG at a command prompt on the Host computer. If you're using Windows 98 or Me, run WINIPCFG on the Host computer. Either way, you'll get an address that looks like xxx.xxx.xxx.xxx (where the x's represent numbers).
a.) Then, go to one of your Client machines, and type the following:
b.) PING -f -l 1500 xxx.xxx.xxx.xxx
(where xxx.xxx.xxx.xxx is the gateway address you obtained in the first step). You'll probably get an error message indicating that it must be fragmented. If you do, type the following:
c.) PING -f -l 1492 xxx.xxx.xxx.xxx
If that doesn't work, try this:
d.) PING -f -l 1472 xxx.xxx.xxx.xxx
2. The numbers in each of these examples (1500, 1492, 1472) are the MTU values. Continue issuing this command with lower and lower MTU numbers until you get ping responses instead of an error message. The highest MTU value that works is the one you need to be using. If an MTU of 1500 (the first command, above) does not produce an error, then this solution won't work for you.
The next step is to configure all your Client computers to use the new, lower MTU as the default for all Internet communication.
Windows 2000 and XP:
1. Run the Registry Editor (REGEDIT.EXE) on one of your "Client" machines.
2. Navigate to HKEY_LOCAL_MACHINE\ SYSTEM\ CurrentControlSet\ Services\ Tcpip\ Parameters\ Interfaces
3. There should be several subkeys under the Interfaces key; most likely, you'll find three. View the contents of each key by clicking, and find the one that corresponds to your primary network adapter; it will be the one with more values than the other two, and will have an IP address value set to something like 192.168.0.x.
4. Once you've found the correct subkey, create a new DWORD value in it (Edit -> New -> DWORD Value), and name the value MTU.
5. Double-click the new value, choose the Decimal option, and type the MTU value determined above.
6. Click Ok when you're done - you'll need to restart Windows for this change take effect.
7. Repeat this for each Client machine.
Windows 98/Me:
1. Run the Registry Editor (REGEDIT.EXE) on one of your "Client" machines.
2. Navigate to HKEY_LOCAL_MACHINE\ System\ CurrentControlSet\ Services\ Class\ Net
3. Under that branch, find a key (numbered, such as 0005) that contains has TCP/IP assigned to the DriverDesc value.
4. Select New from the Edit menu, then String Value, and type MaxMTU for the name of the new value.
5. Double-click the new value, choose the Decimal option, and type the MTU value determined above.
6. Click Ok when you're done - you'll need to restart Windows for this change take effect.
7. Repeat this for each Client machine.
RESULTS WILL VARY
No matter how good your systems may be, they're only as effective as what you put into them.
posted by Chancellor Bear at 8:35 PM
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