yahoo mail and MTU problem

iamswift

New Member
Messages
8
There is this peculiar problem I'm facing with MTU settings.

I'm using PPPoE with wifi enabled on Windows 8.1.

Couple of months back:
* ADSL MTU setting was promptly set to 1492 (8 bytes for PPPoE header discounted).
All of a sudden, yahoo mail was not accessible.
When I tried
Code:
ping -f -l 1464 mail.yahoo.com
Packet needs to be fragmented but DF set. 
Packet needs to be fragmented but DF set.
Packet needs to be fragmented but DF set.
Packet size of 1464 (MTU:1492 - 28 bytes for adjusting different header size) is big. So decided to change MTU.
I checked for various packet sizes; First ping was OK for packet size of 1452. So MTU can be set at 1480.
I changed the MTU to 1480 in modem setting and restarted.
When connected, I tried yahoo mail again - and again failed.
I checked the MTU which is set at 1480. I tried ping with packet size of 1452 and got surprise. I got "Packet needs fragment" again. The same size was working earlier.
I repeated the process. Now the MTU came to 1460. I set the MTU again in modem and restart and try yahoo mail again to get the same failure.
Again I ping with packet size 1432. Nope. Got "Needs fragment" error.
Changed MTU setting in Modem to 1400 - retry cycle - same issue.
Changed MTU setting in model to 1300 - retry - same issue.

Then I came across setting MTU for interfaces in PC.
So reverted the MTU to 1492 in modem.
Set the PC interface MTU as below. I set it for WiFi interface as I was using wireless Internet access.
Code:
netsh interface ipv4 set subinterface "Wi-Fi" mtu=1460 store=persistent
This solved the problem and I was happy.

Fast forward to current day.
Today I couldn't access yahoo mail.
Checked the MTU setting for PC wifi interface. It has been reverted to 1500 (default). May be some windows update did that.
I set it back to 1460. Tried to access yahoo mail. Still not accessible.
Checked the ping with size of 1432 (for MTU 1460). Got "Needs fragment" error.
Checked ping with packet size 1400 - OK - change interface MTU to 1420 - Still couldn't access yahoo.
Checked ping with pkt size 1400 - now not OK.

Checked ping pkt size 1360 - OK - Change interface MTU to 1300 - still couldn't access yahoo mail.
Checked ping pkt size of 1360 - now not OK.

This seems to be vicious cycle.
Any one has an idea what is happening?
 

My Computer

System One

  • OS
    Win 8.1 64 bit
    Computer type
    Laptop
    System Manufacturer/Model
    Lenovo L530
    CPU
    i5 3230M @ 2.6 GHz
    Memory
    4GB
It is not a Yahoo issue. It is a ISP issue. You need to stop making changes on your computer. Windows 8.x.x will just erase them and adjust its network settings according to the speed of the connection.
 

My Computer

System One

  • OS
    Linux Mint 17.2
    Computer type
    Laptop
    System Manufacturer/Model
    Toshiba Satellite C850D-st3nx1
    CPU
    AMD E1-1200 APU with Radeon (tm) HD Graphics 1.40 GHZ
    Memory
    12GB
    Graphics Card(s)
    AMD Radeon™ HD 7310 Graphics
    Sound Card
    Realtek HD
    Monitor(s) Displays
    LCD
    Screen Resolution
    1366 x 768
    Hard Drives
    Crucial M500 240GB SSD
    Mouse
    Logitech M525
    Internet Speed
    45/6 - ATT U-Verse
    Browser
    Google Chrome
    Antivirus
    None needed. It is Linux.
    Other Info
    Arris NVG589 Gateway; Router - Cisco RV320; Switch - Netgear GS108 8-Port Switch & Trendnet TEG-S50g 5-Port Switch; Access Points - Engenius ECB350, Trendnet TEW-638APB; NAS - Lenovo ix2-4; Printer - Brother HL-2280DW; Air Print Server - Lantronix XPrintServer

    A/V UPS - Tripp-Lite Smart 1500LCD 1500 Va/900 W.
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