Cannot access these sites!? Why?

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Ashvon

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Folks,
I have subscribed to 256kbps/unlimited download plan. Am happy with the speed (download/upload). However, have recently noticed that certain legal and legitimate sites are not able to load in IE-browser. No particular error message but...the page seems to be loading successfully forever -until you give up and close the website/broswer-window. Other websites entered in a different window load instantly.

Some of the websites where I have noticed problems and am unable to access are:
www.hotmail.com (Also, unable to sign-in to MSN-Messenger)
http://finance.yahoo.com/
www.marketwatch.com

My primary/secondary DNS-server IPs are set as recommended by Airtel. Any help or yr experience in accessing these sites will be very much appreciated.
Thanks-Ash
 
all these sites work fine on airtel here. contact the customer care adn complain.
 
this did happen sometime with my old ISP. Never did find out why...
 
I think i know why.... i used to face the same problem a few months back.Try this : go to internet options > advanced n hit restore defaults.This should fix the problem, if it doesn't lemme know 🙂p.s the problem is that ie is not asking you to accept a certificate/or the warning message where it says the line is not secured or sumthing 😛have you tried using any other browser ? like firefox or opera ....
 
Originally posted by Ashvon@Nov 6 2005, 12:57 PM
Some of the websites where I have noticed problems and am unable to access are:
www.hotmail.com  (Also, unable to sign-in to MSN-Messenger)
http://finance.yahoo.com/
www.marketwatch.com

My primary/secondary DNS-server IPs are set as recommended by Airtel. Any help or yr experience in accessing these sites will be very much appreciated.
Thanks-Ash
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I had this problem too when i first started with Airtel, they told me to decrease my MTU to 1470. The default is 1500. Now the web works fast...This MTU value was to match the exchanges they have in my area.

But i'm beginning to suspect it slows down my downloads since most servers out there will be set to 1500. I need to do more research in this area.
 
No blr_p, they are right. 1500bytes is the unit size across lans. Since you overhead for atm (and tcp?) is higher, tou have to compensate for them.
I have a method to find the optimim mtu. Type in
Code: 
ping google.com -f -l 1452
and see. If the answer is 'DF is set' or something, you need to lower the last number. Else if the ping is successful, increase the number and try again. You will find a number that _just_ makes it through. This is the mtu for the path. For me 1452 was it.
Let me know if I have a flawed theory here.
 

for me its just 1372... damn!(bsnl home 500 plan)edit😱ops, after some checking... 1464 works for mesteps:my modem MTU was 1400 above.i set the MTU on my modem to 5000 - it shows actual MTU as 1492... so set it back to 1492 then did the pings as above to get 1464...so now my modem has MTU 1492 and my Windows registry has it as 1464... is this good?
 
I checked the tweaks faq in that site and they give the extra piece of information that I forgot to add. The 145* value you get is for the raw ping packet. You need to add IP overhead of 28 bytes to get the max mtu.
Also check out this site.
 
1. Your Tweakable Settings:Receive Window (RWIN): 33396 Window Scaling: 0 Path MTU Discovery: ON RFC1323 Window Scaling: ON RFC1323 Time Stamping: ON Selective Acks: ON MSS requested: 1452 TTL🙁less any hops behind firewall) 132 TTL remaining: 116 TOS/TOS subfield: 0 TOS/Flags: 2. Test 1016149 byte download Actual data bytes sent: 1030669Actual data packets: 711Max packet sent (MTU): 1492Max packet recd (MTU): 1492Retransmitted data packets: 10sacks you sent: 96pushed data pkts: 73data transmit time: 64.954 secsour max idletime: 1427.3 mstransfer rate: 6489 bytes/sectransfer rate: 51 kbits/secThis is not a speed test!transfer efficiency: 98% These were my results, now wt's my ideal MTU. Even i was getting 1464 with the google method.Also, is changing the MTU value in the router settings enough?...or are there some settings one needs to change in windows too?....And what is MRU?...anythin imp?
 
We have almost hijacked this thread.That first block (1. Your Tweakable Settings) tells you the optimum for your connection. Download the tcp doctor from the same site and set the mtu and other settngs mentioned there.MRU? AFAIK, MRU stands for 'Most Recently Used'. As in the recently used file list in MS Word's File menu 🙂I suppose you are asking about MTU. MTU is Maximum Transmission Unit. When your modem sends data out, it has to break large data into some size. This size depends on the ISP's network type. The MTU dictates how big a packet can to be. For more explaination, visit the link in my previous post.
 
ah yes, i remember the 28 byte number (IP header or whatever) - actually i think its 20 bytes for something and anothr 8 bytes for something else 😛so the "physical" MTU is 1492... (as the modem shows for me)... and the OS/software MTU should be that number minus 28, which is 1464... so the numbers look right...i used to leave my MTUs at 1400 just to have a buffer... but i'll try 1464 on both my connections (bsnl home 1800 and home 500) to see if i can get some extra speed
 
hmm...these values should be detected correctly by Windoze.... Ah well its windoze after all 😉
 
Originally posted by SiriusB@Nov 6 2005, 08:10 PM
I have a method to find the optimim mtu. Type in
Code: 
ping google.com -f -l 1452
and see. If the answer is 'DF is set' or something, you need to lower the last number. Else if the ping is successful, increase the number and try again. You will find a number that _just_ makes it through. This is the mtu for the path. For me 1452 was it.
Let me know if I have a flawed theory here.
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I tried this test and it seems my ideal MTU is 1442 which gives a successful ping. Anything above that gives
Code: 
Pinging google.com [64.233.187.99] with 1443 bytes of dataPacket needs to be fragmented but DF set.Packet needs to be fragmented but DF set.Packet needs to be fragmented but DF set.Packet needs to be fragmented but DF set.Ping statistics for 64.233.187.99:    Packets: Sent = 4, Received = 0, Lost = 4 (100% loss),
I need to check this with the Airtel CC as it's really dependant on what MTU the particular model of exchange is being used. I suspect this is why ppl are getting slightly different ideal values.

http://www.mynetwatchman.com/kb/adsl/pppoemtu.htm
Thx for this link gives a good explanation but has to take into account what MTU the exchange is using. But it only gives a 0.6% improvement. I was hoping for more.

Originally posted by max@Nov 7 2005, 12:37 PM
hmm...these values should be detected correctly by Windoze.... Ah well its windoze after all 😉
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Heh, how does windows know you are using PPP over ATM. There is an extra wrapper (imposed by the ISP) that ATM uses around TCP/IP.

The same tweak would be required on *nix as well. All windows or any other OS implementing TCP/IP does is make sure that tcp protocol only is being used properly.
 
Hi Folks,I would like to CLOSE this thread....The final action to resolve my problem was a phone-call to AIRTEL customer-service. The personnel was excellent and took me through the steps to Log-in into the Modem-(WebDistributor) settings and do some changes. Then, I was asked to TELNET into this IP...and do some commands....and Then reboot the laptop....And it worked like magic!!All the websites that were giving a problem now load smoothly!Thanks-Ashish
 

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