|
Thread Index [isp-bgp] Re: Please help me..
DM> Date: Wed, 23 Jun 2004 21:38:03 +0700 DM> From: Dwi Mahindra DM> EDDY>What happens if you telnet to port 80 of the sites that don't DM> EDDY>work? Do you establish the connection? DM> DM> I can telnet port 80 and session has established DM> This following the capture result from host/PC : Okay. It's not a BGP problem. If the problem were BGP-related, you'd be unable to connect. I've found many people learning about BGP also need to learn about this, so I'll keep the mail on-list a bit longer. Someone flame me if I go too far off- topic. :) DM> C:\>telnet 202.130.175.172 80 Now try connecting via telnet and typing GET / HTTP/1.0 followed by pressing the <ENTER> key twice. Does the page ever come up? If not, it's probably an MTU problem. DM> What the meaning of path MTU and how I check it ? http://www.google.com/search?q=%22path+mtu%22 Depending on your version of Windows, use the "ping" command with "do not fragment" set. DM> So what I must be do to solve it ? Make sure ICMP type 3 is not blocked anywhere along the path. Unfortunately, I think the problem is with the shangintranet.com site. Here's why: * As a test, I did a "dig +norec @shangintranet.com foo." to send a UDP packet to shangintranet.com. Normally, a server that doesn't allow that will send an ICMP error message. I received a DNS timeout, which indicates 1) the DNS request was dropped silently, or 2) someone is blocking ICMP unreachables. * I decreased my MTU to 1496 and tried pulling up the Web page. Nothing happened. I set my MTU back to 1500, and the site loaded instantly. I suspect you have something limiting your MTU, such as PPPoE, GRE, or MPLS. That's not standard, but that's not the problem -- sites MUST allow ICMP unreachables for MTU discovery. When someone foolishly blocks ICMP type 3 (like shangintranet.com is doing), it breaks things for people with smaller MTUs. Eddy -- EverQuick Internet - http://www.everquick.net/ A division of Brotsman & Dreger, Inc. - http://www.brotsman.com/ Bandwidth, consulting, e-commerce, hosting, and network building Phone: +1 785 865 5885 Lawrence and [inter]national Phone: +1 316 794 8922 Wichita _________________________________________________________________ DO NOT send mail to the following addresses: davidc@... -*- jfconmaapaq@intc.net -*- sam@everquick.net Sending mail to spambait addresses is a great way to get blocked. To unsubscribe via postal mail, please contact us at: Jupitermedia Corp. Attn: Discussion List Management 475 Park Avenue South New York, NY 10016 Please include the email address which you have been contacted with.
Thread Index |
|
