Thread: Some Sites are not opening

I have broandband business plan 3300,

sometimes my connection fails to open some sites , next day it can open.

dunno why

on otherside, my friends are able to open sites which i cant at same time

what should be wrong ?

It's probably a DNS issue.. change your DNS servers to OPENDNS ..their ip's are 208.67.222.222 and 208.67.220.220

The MTU Value needs to be changed.

Open the Configuration page>>>>go to the Setup>>>

Select BSNL>>>>>change the MTU value from 1492 to 1452>>>apply

Go to tools>>>>system Commands>>>>click save all.

Originally Posted by bhvm

The MTU Value needs to be changed.

Open the Configuration page>>>>go to the Setup>>>

Select BSNL>>>>>change the MTU value from 1492 to 1452>>>apply

Go to tools>>>>system Commands>>>>click save all.

But how ?

i couldnt find that.

i have ZTE modem

Originally Posted by anantthakor

But how ?

i couldnt find that.

i have ZTE modem

For D-link Modem,
Type 192.168.1.1 into your browser.
User name are passowrds are 'Admin'

I am not sure about ZTE tough. Please refer your documentation.

As we know thet internet Data is transferred into groups called 'packets'. MTU is short for 'Maximun Transfer unit.
The MTU value is in Bytes.This will specify how Large a Single packet would be.

D-link defaults their MTU at 1492, however many servers are incapable of this, and site loading fails. 1452 is much stable value.

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 (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 ).