Thread: How do i configure my MTU?

Well when i try connecting to xbox live it gives me an error message and tells me that it's unable to connect because my MTU is below 1364. My question is how do i configure it, i've been told type in192.168.1.1, i did, tried logging in with Acc:admin and password: admin, didn't work. Anyone got an idea?
Thanks again.

try password as root or password.

didn't work =/

You (or whever configured the modem) must have changed the admin password when it was configured last time.

You may have to reset the modem and configure the modem all over again.

Mention the make and model number of the modem.

It's a Tenda D840R

1.
Tried earlier ?
Start RUN cmd OK New window
type Ipconfig /all
Modem IP is shown.
or
2. Start RUN type cmd OK
New window
Ping 192.168.0.1
IF you get response
THEN
Log in to the router setup page at http://192.168.0.1
(username: admin password: admin)

Feedback

tried it, doesen't work.

ok.

Have you tried reseting the modem to factory defaults?

(before you do that, be warned that all your settings will be lost).

Not all that great with modems, how do i reset it?

If you do not know how to configure the modem, then it is best not to reset it.

If you wish to reset anyway, locate the RESET button on the back panel (on some modems, this is located on the bottom panel). The button will be located well inside a pin hole.

Power on the modem, and using a matchstick or toothpick, press the RESET button for 15 to 20 seconds. All the LEDs on the modem will flash when the reseting happens. All previous settings are lost and the modem is reset to factory settings. The default username/password become "admin/admin" again.

Refer to the modem setup instructions here: D840R ADSL2+ Router-ADSL2+ Modem-Tenda

Use the guides in this forum for reference. See the Broadband How to section.

Well i reset it to factory results, logged in, adjusted my settings to how they were but i can't find anything related to MTU, is is possible that my modem has a non-adjustable MTU?

Some routers do not provide any option to set MTU.

well that sucks = /

Can any one tell why is it so important to set MTU? I leave it to default value of 1500.

I don't think its important. its usually to be modified only if you face any problem. some network may not be capable of transmitting to the maximum capacity OR some of them are designed to handle lower size of data packets, in which case there may be loss of data.

sometimes it can be irrelevent too :
for example: in my case, in PPPoE mode alone, many websites don't open at all unless proper MTU is set, but they work just fine in case of bridge mode.

Originally Posted by newprouser

sometimes it can be irrelevent too :
for example: in my case, in PPPoE mode alone, many websites don't open at all unless proper MTU is set, but they work just fine in case of bridge mode.

I have been using openDNS for a long time. Recently I have been facing problems opening some website in firefox. this problem is not regular a regular occurance. Initially I thought it was a problem with DNS...but its openDNS...and its supposed to be issue free?

Coud this be related to the MTU settings?

No harm in trying.

use the software "TCP Optimizer". run the largest MTU test.

Originally Posted by newprouser

No harm in trying.

use the software "TCP Optimizer". run the largest MTU test.

ok will try and post the feedback here.

MTU needs to be less or equal than the smallest MTU value in connected remote hosts. As the packet travels through many router to reach the destination any conflict in MTU size will result in packet drop and returning a ICMP "HOST UNREACHABLE" message , using this message usually ur machine will try to correct his own MTU value (defined in RFC1191) .But few of the router in the network path may have firewall installed which blockes those ICMP message , preventing MTU correction. (I have seen this with few microsoft sites).

It's best to change the MTU to a optimum low value (but too small value will result in more fragmentation ,i.e. same message will be split in many small parts). Also be clear that if underlying ISP uses ATM to transfer the IP packets then it should be multiple of 48 bytes (max cell/packet size in ATM) for optimum transmission.

Most of the BSNL's 59.xxx series IP doesn't have such MTU releasted issues. Most of the problem is seen in 117.xxx series. (I donno why ).