From owner-freebsd-current@FreeBSD.ORG Sat Apr 23 12:29:10 2005 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 8000316A4CE for ; Sat, 23 Apr 2005 12:29:10 +0000 (GMT) Received: from mail.sorbs.net (mail.sorbs.net [203.15.51.62]) by mx1.FreeBSD.org (Postfix) with ESMTP id F1CBE43D2D for ; Sat, 23 Apr 2005 12:29:09 +0000 (GMT) (envelope-from matthew@uq.edu.au) Received: from [10.200.254.98] by nemesis.sorbs.net (iPlanet Messaging Server 5.2 HotFix 1.21 (built Sep 8 2003)) with ESMTPSA id <0IFE00K06G18J8@nemesis.sorbs.net> for freebsd-current@freebsd.org; Sat, 23 Apr 2005 22:29:33 +1000 (EST) Date: Sat, 23 Apr 2005 22:27:53 +1000 From: Matthew Sullivan In-reply-to: <42663EA1.3020409@uq.edu.au> To: freebsd-current@freebsd.org Message-id: <426A3F49.6090203@uq.edu.au> MIME-version: 1.0 Content-type: multipart/signed; boundary=------------ms080202010405040106090400; micalg=sha1; protocol="application/x-pkcs7-signature" X-Accept-Language: en User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.5) Gecko/20041231 References: <426426AE.2060406@uq.edu.au> <20050420084413.GA27304@walton.maths.tcd.ie> <42663EA1.3020409@uq.edu.au> Subject: Re: DF (Don't frag) issues X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 23 Apr 2005 12:29:10 -0000 This is a cryptographically signed message in MIME format. --------------ms080202010405040106090400 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Matthew Sullivan wrote: > I'm going to post this back to the list as Marko was also helping me get > to the bottom of it... > > David Malone wrote: > >> On Tue, Apr 19, 2005 at 07:29:18AM +1000, Matthew Sullivan wrote: >> >> >>> Any reason why FreeBSD 5.2.1+ and 5.3-p9 set DF on all packets? >>> >> >> >> It is usual to do this to do path MTU discovery with TCP. I don't >> know what the situation with the packets that the VPN sends is. > Ok well thanks to Andrew @ Supernews and a lot of debugging it appears there is a bug.... sys/netinet/ip_icmp.c: line 440 if (!mtu) mtu = ip_next_mtu(mtu, 1); Problem is ip_next_mtu will always return 0 when called with (0, 1) ... so following that with: if (mtu >= max(296, (tcp_minmss + sizeof(struct tcpiphdr)))) tcp_hc_updatemtu(&inc, mtu); and nothing gets changed.... hence why it fails. Apparently the gateway should be suggesting a MTU value for use.... the gateway is also FreeBSD 5.3 so something needs fixing .. :-/ Regards, -- Matthew Sullivan Specialist Systems Programmer Information Technology Services The University of Queensland --------------ms080202010405040106090400 Content-Type: application/x-pkcs7-signature; name="smime.p7s" Content-Transfer-Encoding: base64 Content-Disposition: attachment; filename="smime.p7s" Content-Description: S/MIME Cryptographic Signature MIAGCSqGSIb3DQEHAqCAMIACAQExCzAJBgUrDgMCGgUAMIAGCSqGSIb3DQEHAQAAoIIG7DCC A3IwggJaoAMCAQICASowDQYJKoZIhvcNAQEEBQAwgaMxCzAJBgNVBAYTAkFVMRMwEQYDVQQI EwpRdWVlbnNsYW5kMREwDwYDVQQHEwhCcmlzYmFuZTElMCMGA1UEChMcVGhlIFVuaXZlcnNp dHkgb2YgUXVlZW5zbGFuZDEoMCYGA1UECxMfSW5mb3JtYXRpb24gVGVjaG5vbG9neSBTZXJ2 aWNlczEbMBkGA1UEAxMSQ2VydGlmaWNhdGUgU2VydmVyMB4XDTA0MDEyMTIzMzYyMVoXDTA2 MDEyMTIzMzYyMVowgbIxCzAJBgNVBAYTAkFVMSUwIwYDVQQKExxUaGUgVW5pdmVyc2l0eSBv ZiBRdWVlbnNsYW5kMScwJQYDVQQLEx5JbmZvcm1hdGlvbiBUZWNub2xvZ3kgU2VydmljZXMx FjAUBgoJkiaJk/IsZAEBEwZjY21hdHQxGTAXBgNVBAMTEE1hdHRoZXcgU3VsbGl2YW4xIDAe BgkqhkiG9w0BCQEWEW1hdHRoZXdAdXEuZWR1LmF1MFwwDQYJKoZIhvcNAQEBBQADSwAwSAJB AJsUfrw/QUqKIzDverWc2F4GFFRZmIeO+bAl+7BM6x/9frMzOtygx4QGb4oQwtOE8Sda1aIs v+yJF3Di9EuUyvMCAwEAAaNoMGYwDgYDVR0PAQH/BAQDAgXgMBEGCWCGSAGG+EIBAQQEAwIF oDAfBgNVHSMEGDAWgBQmqtoyueiWTYZBinvsnzeOWLtUuzAgBgNVHREEGTAXgRVtYXR0aGV3 QGl0cy51cS5lZHUuYXUwDQYJKoZIhvcNAQEEBQADggEBAF2gZrkqZsZlHd4K/+yBN6qrpD61 hctDf7/Eg4jk6DMknEs6nvHMFUMZ4SXvkqPLnHBygTARKAs7qBSLd7mUUBOOQEgk6ovQVY6S 1CDSt3P9O6wjG0K1igtk8v6u7lkQ8p2STXqrOePVINdaucUgBO/IpeUtt9ATl1qvPTWyM/fz oUZsIKeYjNQVEQsuimrZjdbIAFxdl1fggSngUv64wBn8wCssGrPZIZA2lpBBEW1wejoWrDOH IIr+SspGd0i8MovDTMRSvgTERLki17FU/ANilcrSXiODKeIvpXhnQqVScnsoMSZmBmN2QIoG SnBjNK5mYxx5E3v20VOwtP1hVdEwggNyMIICWqADAgECAgEqMA0GCSqGSIb3DQEBBAUAMIGj MQswCQYDVQQGEwJBVTETMBEGA1UECBMKUXVlZW5zbGFuZDERMA8GA1UEBxMIQnJpc2JhbmUx JTAjBgNVBAoTHFRoZSBVbml2ZXJzaXR5IG9mIFF1ZWVuc2xhbmQxKDAmBgNVBAsTH0luZm9y bWF0aW9uIFRlY2hub2xvZ3kgU2VydmljZXMxGzAZBgNVBAMTEkNlcnRpZmljYXRlIFNlcnZl cjAeFw0wNDAxMjEyMzM2MjFaFw0wNjAxMjEyMzM2MjFaMIGyMQswCQYDVQQGEwJBVTElMCMG A1UEChMcVGhlIFVuaXZlcnNpdHkgb2YgUXVlZW5zbGFuZDEnMCUGA1UECxMeSW5mb3JtYXRp b24gVGVjbm9sb2d5IFNlcnZpY2VzMRYwFAYKCZImiZPyLGQBARMGY2NtYXR0MRkwFwYDVQQD ExBNYXR0aGV3IFN1bGxpdmFuMSAwHgYJKoZIhvcNAQkBFhFtYXR0aGV3QHVxLmVkdS5hdTBc MA0GCSqGSIb3DQEBAQUAA0sAMEgCQQCbFH68P0FKiiMw73q1nNheBhRUWZiHjvmwJfuwTOsf /X6zMzrcoMeEBm+KEMLThPEnWtWiLL/siRdw4vRLlMrzAgMBAAGjaDBmMA4GA1UdDwEB/wQE AwIF4DARBglghkgBhvhCAQEEBAMCBaAwHwYDVR0jBBgwFoAUJqraMrnolk2GQYp77J83jli7 VLswIAYDVR0RBBkwF4EVbWF0dGhld0BpdHMudXEuZWR1LmF1MA0GCSqGSIb3DQEBBAUAA4IB AQBdoGa5KmbGZR3eCv/sgTeqq6Q+tYXLQ3+/xIOI5OgzJJxLOp7xzBVDGeEl75Kjy5xwcoEw ESgLO6gUi3e5lFATjkBIJOqL0FWOktQg0rdz/TusIxtCtYoLZPL+ru5ZEPKdkk16qznj1SDX WrnFIATvyKXlLbfQE5darz01sjP386FGbCCnmIzUFRELLopq2Y3WyABcXZdX4IEp4FL+uMAZ /MArLBqz2SGQNpaQQRFtcHo6FqwzhyCK/krKRndIvDKLw0zEUr4ExES5ItexVPwDYpXK0l4j gyniL6V4Z0KlUnJ7KDEmZgZjdkCKBkpwYzSuZmMceRN79tFTsLT9YVXRMYIDQDCCAzwCAQEw gakwgaMxCzAJBgNVBAYTAkFVMRMwEQYDVQQIEwpRdWVlbnNsYW5kMREwDwYDVQQHEwhCcmlz YmFuZTElMCMGA1UEChMcVGhlIFVuaXZlcnNpdHkgb2YgUXVlZW5zbGFuZDEoMCYGA1UECxMf SW5mb3JtYXRpb24gVGVjaG5vbG9neSBTZXJ2aWNlczEbMBkGA1UEAxMSQ2VydGlmaWNhdGUg U2VydmVyAgEqMAkGBSsOAwIaBQCgggItMBgGCSqGSIb3DQEJAzELBgkqhkiG9w0BBwEwHAYJ KoZIhvcNAQkFMQ8XDTA1MDQyMzEyMjc1M1owIwYJKoZIhvcNAQkEMRYEFI/9e5MFw1OVhtd8 0ESWKfoM9ZmhMFIGCSqGSIb3DQEJDzFFMEMwCgYIKoZIhvcNAwcwDgYIKoZIhvcNAwICAgCA MA0GCCqGSIb3DQMCAgFAMAcGBSsOAwIHMA0GCCqGSIb3DQMCAgEoMIG6BgkrBgEEAYI3EAQx gawwgakwgaMxCzAJBgNVBAYTAkFVMRMwEQYDVQQIEwpRdWVlbnNsYW5kMREwDwYDVQQHEwhC cmlzYmFuZTElMCMGA1UEChMcVGhlIFVuaXZlcnNpdHkgb2YgUXVlZW5zbGFuZDEoMCYGA1UE CxMfSW5mb3JtYXRpb24gVGVjaG5vbG9neSBTZXJ2aWNlczEbMBkGA1UEAxMSQ2VydGlmaWNh dGUgU2VydmVyAgEqMIG8BgsqhkiG9w0BCRACCzGBrKCBqTCBozELMAkGA1UEBhMCQVUxEzAR BgNVBAgTClF1ZWVuc2xhbmQxETAPBgNVBAcTCEJyaXNiYW5lMSUwIwYDVQQKExxUaGUgVW5p dmVyc2l0eSBvZiBRdWVlbnNsYW5kMSgwJgYDVQQLEx9JbmZvcm1hdGlvbiBUZWNobm9sb2d5 IFNlcnZpY2VzMRswGQYDVQQDExJDZXJ0aWZpY2F0ZSBTZXJ2ZXICASowDQYJKoZIhvcNAQEB BQAEQG6ngvNgl7nukszVkn0oxNJzvvRiDa7Cnac/dbaSCHHLXS0gG2RLyy6m/o7XM+spWJpG lIX6b/UhUdaXXMRByuEAAAAAAAA= --------------ms080202010405040106090400--