In order to determine the highest MTU setting that will work for an IPSEC VPN over ADSL with PPPoE, you can use the ping command in conjunction with the "do not fragment" setting and the length setting. In a command window, enter the following:
ping -l 1472 -f some.ip.close.to.your.fw Where some.ip.close.to.your.fw is an ip address that is as close as you can be to your fw (e.g. an external router attached to your firewall.) -f means do not fragment -l 1472 sets the 'send buffer size' to 1472 Reduce the ping size in increments (e.g. 10) until you no longer get a "packet needs to be fragmented" error reported back to you, then slowly increase that number to find your max ping size. Add 28 to that number and you'll have your MaxMTU setting. This number should be less than 1492 for PPPoE since PPPoE has an extra 8 byte header reducing the standard 1500 to 1492. -----Original Message----- From: Robert Fowler [mailto:[EMAIL PROTECTED] Sent: Tuesday, August 10, 2004 9:01 AM To: [EMAIL PROTECTED] Subject: [FW-1] SecureClient behind ADSL router with PPPOE I cannot connect to firewall for secureclient from behind a adsl route using PPPOE. I have tried the setup on standard dialup and it works. so happ with config. Below is what i have tried, please let me know if I am missing something. Setup secureclient r55 on windows xp laptop Used the secure client utility mtuadjust to reduce the MTU to 1492 on laptop. Use UDP encapsulation What i have noticed I have noticed that the secureclient reports tunnel MTU properties failed ??? But no reason why ??? Do I need to reduce the MTU on the Nokia Firewall, if so how Thanks --------------------------------- ALL-NEW Yahoo! Messenger - all new features - even more fun! ================================================= To set vacation, Out-Of-Office, or away messages, send an email to [EMAIL PROTECTED] in the BODY of the email add: set fw-1-mailinglist nomail ================================================= To unsubscribe from this mailing list, please see the instructions at http://www.checkpoint.com/services/mailing.html ================================================= If you have any questions on how to change your subscription options, email [EMAIL PROTECTED] ================================================= ================================================= To set vacation, Out-Of-Office, or away messages, send an email to [EMAIL PROTECTED] in the BODY of the email add: set fw-1-mailinglist nomail ================================================= To unsubscribe from this mailing list, please see the instructions at http://www.checkpoint.com/services/mailing.html ================================================= If you have any questions on how to change your subscription options, email [EMAIL PROTECTED] =================================================
