Some web sites fails to load

Issue:

The firewall does not block the sites and no error is reported.

The dns may or may not resolve the domain name

Ping may or may not work for the domain name

All other sites loads fine

Here's what might help:

open command prompt and type the following command

ping ezref.info -f -l 1500

(Lower case F and L)

You will get a reply as under:

Pinging ezref.info [182.50.147.1] with 1500 bytes of data:

Reply from 10.128.1.51: Packet needs to be fragmented but DF set.

Start to reduce the number 1500 in multiples of 8 until the ping works fine.

Example:

ping ezref.info -f -l 1492

ping ezref.info -f -l 1484

ping ezref.info -f -l 1476

ping ezref.info -f -l 1468

Pinging ezref.info [182.50.147.1] with 1468 bytes of data:

Reply from 182.50.147.1: bytes=1468 time=230ms TTL=46

Reply from 182.50.147.1: bytes=1468 time=235ms TTL=46

Reply from 182.50.147.1: bytes=1468 time=220ms TTL=46

Reply from 182.50.147.1: bytes=1468 time=232ms TTL=46

Now go to the WAN interface of your firewall and change the MTU to the number where the ping worked fine.