Date: Fri, 20 Jan 2017 09:28:05 -0500 From: Jon Radel <jon@radel.com> To: dweimer@dweimer.net Cc: FreeBSD Questions <freebsd-questions@freebsd.org> Subject: Re: Tuning Route Cache Message-ID: <c749cde5-7329-822d-7ab2-8c65510fbc75@radel.com> In-Reply-To: <23dc5b28cf21bbea762700e426346d39@dweimer.net> References: <ae39bbc53f3e2f2b1afa3afa93b43fa4@dweimer.net> <28d24a44-9e1c-7c12-d7e8-6f243a350510@radel.com> <23dc5b28cf21bbea762700e426346d39@dweimer.net>
next in thread | previous in thread | raw e-mail | index | archive | help
This is a cryptographically signed message in MIME format. --------------ms050809030909050706080009 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: quoted-printable On 1/20/17 7:49 AM, Dean E. Weimer wrote: > On 2017-01-19 9:04 pm, Jon Radel wrote: >> See >> >> man 8 routed >> >> for more on some of that, including reducing the 30 minutes. >> <snip> >> Even if you want routes learned >> from an ICMP Redirect to be cleaned up automatically, you'll need rout= ed >> to do it for you. See the above referenced man page. My earlier response reduced to the pertinent parts. You have now read the man page where it describes the mechanism that leads routed to clean up routes learned via ICMP Redirect when they stop working, right? You are running routed, right? > The default gateway along with the other routers are in the same subnet= , > so the router responds with a route redirection, then the FreeBSD serve= r > caches that they show up if you do a netstat -rnf inet listing the > remote devices and the next hop. These are staying there at least 11 > hours that I can confirm. I guess maybe a solution would be to set the > server up with a routing protocol and let it talk to the router to get > the updates rather than just receive the re directions. But that seems > overly complex. RIP isn't *that* much more complicated than this chain of correspondence, but of course you'll need the Cicso router admin to play along. >=20 > Perhaps the change needs to occur on the Cisco router so that it sends > an expiration along with the redirect. >=20 >=20 Configuring the router to accurately forecast the future, so it knows when the network admin plans to change the topology, and then inserting that time into a packet that has no field for such data, now that's complicated. You'll need to redo a whole bunch of RFCs. And invent an accurate mechanism for forecasting the future, after which your server will be the very least of your worries. :-) See http://www.networksorcery.com/enp/protocol/icmp/msg5.htm for the details on that; there really isn't a mechanism built into redirects for expiring them. On FreeBSD, the only mechanisms I know about (and on this I'd love it if somebody can tell me about others) for clearing routes learned from a an ICMP Redirect are to manually remove the route or to allow the kernel and routed to interact to start pulling routes when TCP handshakes start timing out. Or you could just reboot your server on a regular basis, but that seems a bit crude. I suppose the closest thing to your original request would be to write a script and drop it into cron that removed all routes with the D (and M?) flags periodically. --=20 --Jon Radel jon@radel.com --------------ms050809030909050706080009 Content-Type: application/pkcs7-signature; name="smime.p7s" Content-Transfer-Encoding: base64 Content-Disposition: attachment; filename="smime.p7s" Content-Description: S/MIME Cryptographic Signature MIAGCSqGSIb3DQEHAqCAMIACAQExDzANBglghkgBZQMEAgEFADCABgkqhkiG9w0BBwEAAKCC Cq8wggSvMIIDl6ADAgECAhEA4CPLFRKDU4mtYW56VGdrITANBgkqhkiG9w0BAQsFADBvMQsw CQYDVQQGEwJTRTEUMBIGA1UEChMLQWRkVHJ1c3QgQUIxJjAkBgNVBAsTHUFkZFRydXN0IEV4 dGVybmFsIFRUUCBOZXR3b3JrMSIwIAYDVQQDExlBZGRUcnVzdCBFeHRlcm5hbCBDQSBSb290 MB4XDTE0MTIyMjAwMDAwMFoXDTIwMDUzMDEwNDgzOFowgZsxCzAJBgNVBAYTAkdCMRswGQYD VQQIExJHcmVhdGVyIE1hbmNoZXN0ZXIxEDAOBgNVBAcTB1NhbGZvcmQxGjAYBgNVBAoTEUNP TU9ETyBDQSBMaW1pdGVkMUEwPwYDVQQDEzhDT01PRE8gU0hBLTI1NiBDbGllbnQgQXV0aGVu dGljYXRpb24gYW5kIFNlY3VyZSBFbWFpbCBDQTCCASIwDQYJKoZIhvcNAQEBBQADggEPADCC AQoCggEBAImxDdp6UxlOcFIdvFamBia3uEngludRq/HwWhNJFaO0jBtgvHpRQqd5jKQi3xdh TpHVdiMKFNNKAn+2HQmAbqUEPdm6uxb+oYepLkNSQxZ8rzJQyKZPWukI2M+TJZx7iOgwZOak +FaA/SokFDMXmaxE5WmLo0YGS8Iz1OlAnwawsayTQLm1CJM6nCpToxDbPSBhPFUDjtlOdiUC ISn6o3xxdk/u4V+B6ftUgNvDezVSt4TeIj0sMC0xf1m9UjewM2ktQ+v61qXxl3dnUYzZ7ifr vKUHOHaMpKk4/9+M9QOsSb7K93OZOg8yq5yVOhM9DkY6V3RhUL7GQD/L5OKfoiECAwEAAaOC ARcwggETMB8GA1UdIwQYMBaAFK29mHo0tCb3+sQmVO8DveAky1QaMB0GA1UdDgQWBBSSYWuC 4aKgqk/sZ/HCo/e0gADB7DAOBgNVHQ8BAf8EBAMCAYYwEgYDVR0TAQH/BAgwBgEB/wIBADAd BgNVHSUEFjAUBggrBgEFBQcDAgYIKwYBBQUHAwQwEQYDVR0gBAowCDAGBgRVHSAAMEQGA1Ud HwQ9MDswOaA3oDWGM2h0dHA6Ly9jcmwudXNlcnRydXN0LmNvbS9BZGRUcnVzdEV4dGVybmFs Q0FSb290LmNybDA1BggrBgEFBQcBAQQpMCcwJQYIKwYBBQUHMAGGGWh0dHA6Ly9vY3NwLnVz ZXJ0cnVzdC5jb20wDQYJKoZIhvcNAQELBQADggEBABsqbqxVwTqriMXY7c1V86prYSvACRAj mQ/FZmpvsfW0tXdeDwJhAN99Bf4Ss6SAgAD8+x1banICCkG8BbrBWNUmwurVTYT7/oKYz1gb 4yJjnFL4uwU2q31Ypd6rO2Pl2tVz7+zg+3vio//wQiOcyraNTT7kSxgDsqgt1Ni7QkuQaYUQ 26Y3NOh74AEQpZzKOsefT4g0bopl0BqKu6ncyso20fT8wmQpNa/WsadxEdIDQ7GPPprsnjJT 9HaSyoY0B7ksyuYcStiZDcGG4pCS+1pCaiMhEOllx/XVu37qjIUgAmLq0ToHLFnFmTPyOInl tukWeh95FPZKEBom+nyK+5swggX4MIIE4KADAgECAhBzVOU8fWu0zQ1gaQ38zgEbMA0GCSqG SIb3DQEBCwUAMIGbMQswCQYDVQQGEwJHQjEbMBkGA1UECBMSR3JlYXRlciBNYW5jaGVzdGVy MRAwDgYDVQQHEwdTYWxmb3JkMRowGAYDVQQKExFDT01PRE8gQ0EgTGltaXRlZDFBMD8GA1UE AxM4Q09NT0RPIFNIQS0yNTYgQ2xpZW50IEF1dGhlbnRpY2F0aW9uIGFuZCBTZWN1cmUgRW1h aWwgQ0EwHhcNMTUwMzMwMDAwMDAwWhcNMTgwMzI5MjM1OTU5WjCB+jELMAkGA1UEBhMCVVMx DjAMBgNVBBETBTIyMTUwMQswCQYDVQQIEwJWQTEUMBIGA1UEBxMLU3ByaW5nZmllbGQxGjAY BgNVBAkTETY5MTcgUmlkZ2V3YXkgRHIuMRUwEwYDVQQKEwxKb24gVC4gUmFkZWwxMjAwBgNV BAsTKUlzc3VlZCB0aHJvdWdoIEpvbiBULiBSYWRlbCBFLVBLSSBNYW5hZ2VyMR8wHQYDVQQL ExZDb3Jwb3JhdGUgU2VjdXJlIEVtYWlsMRIwEAYDVQQDEwlKb24gUmFkZWwxHDAaBgkqhkiG 9w0BCQEWDWpvbkByYWRlbC5jb20wggEiMA0GCSqGSIb3DQEBAQUAA4IBDwAwggEKAoIBAQDe 1Rth9hbQqaODn++C5dVAQH9nM2VH3oPazZufOwmIG2SXI/v3PuemcQQ3JkhmpQ06gYszyXbk TCLsqvEfalYj81jdt/K5lT4aVdj0LfJIWyTcU95V2rsCuHsSvn/PnIcsEtXg53rCtqS4EOtJ 9u3rY2hP8YCiyz1yY3mn4nKJs93MHG4AkXYuVpzfaIADETcVrA+razvXEfnDJXXDZZ9ZuuV1 06yIovOvhYWSlaVu8nrSHJjXFZI2IXwgIeVBoMih3yu6LLj14I/YdZ0rIA8K+UNB+NW6Ri3u wHXBbr4jh3ZqkrqIVUrf1VeybhdrJcdqXdMNHjKDSlCoaxYRbLy1AgMBAAGjggHVMIIB0TAf BgNVHSMEGDAWgBSSYWuC4aKgqk/sZ/HCo/e0gADB7DAdBgNVHQ4EFgQUz9YB10WEfBNHskRw o/0vh8qaQuwwDgYDVR0PAQH/BAQDAgWgMAwGA1UdEwEB/wQCMAAwHQYDVR0lBBYwFAYIKwYB BQUHAwQGCCsGAQUFBwMCMEYGA1UdIAQ/MD0wOwYMKwYBBAGyMQECAQMFMCswKQYIKwYBBQUH AgEWHWh0dHBzOi8vc2VjdXJlLmNvbW9kby5uZXQvQ1BTMF0GA1UdHwRWMFQwUqBQoE6GTGh0 dHA6Ly9jcmwuY29tb2RvY2EuY29tL0NPTU9ET1NIQTI1NkNsaWVudEF1dGhlbnRpY2F0aW9u YW5kU2VjdXJlRW1haWxDQS5jcmwwgZAGCCsGAQUFBwEBBIGDMIGAMFgGCCsGAQUFBzAChkxo dHRwOi8vY3J0LmNvbW9kb2NhLmNvbS9DT01PRE9TSEEyNTZDbGllbnRBdXRoZW50aWNhdGlv bmFuZFNlY3VyZUVtYWlsQ0EuY3J0MCQGCCsGAQUFBzABhhhodHRwOi8vb2NzcC5jb21vZG9j YS5jb20wGAYDVR0RBBEwD4ENam9uQHJhZGVsLmNvbTANBgkqhkiG9w0BAQsFAAOCAQEAS1Pe +gBgP+SQ/a5I5e7zX0Rg0DhH378LHlZixJgS6LfCPL2edKMUQi3Th9GXfLjdeyeWuMWoz925 ZzBHcPwkBeH+iM/AEhu0Dhi0kop/p66g9tEPJUZ/KDsqxddNDrD0Typn3/33pHTjJEDqydzA gwB0Nn8blpMbqSwT+j8wuPakfLsj1cSDzXrTLLsmIQB7auAyaYXdWyW8Yqw336rLUCvjOUfn qOOyjVsieTw/0PLoOHJaGyez+VtV4eyi6p1SNiX32A+fvxBMzKQLCokE43cXItc9Okzq//f2 fuvGp17r8mpm4OjjM5E2kwsg9bBPUBMR4/sxosKVLn0o9rxlozGCBEEwggQ9AgEBMIGwMIGb MQswCQYDVQQGEwJHQjEbMBkGA1UECBMSR3JlYXRlciBNYW5jaGVzdGVyMRAwDgYDVQQHEwdT YWxmb3JkMRowGAYDVQQKExFDT01PRE8gQ0EgTGltaXRlZDFBMD8GA1UEAxM4Q09NT0RPIFNI QS0yNTYgQ2xpZW50IEF1dGhlbnRpY2F0aW9uIGFuZCBTZWN1cmUgRW1haWwgQ0ECEHNU5Tx9 a7TNDWBpDfzOARswDQYJYIZIAWUDBAIBBQCgggJhMBgGCSqGSIb3DQEJAzELBgkqhkiG9w0B BwEwHAYJKoZIhvcNAQkFMQ8XDTE3MDEyMDE0MjgwNVowLwYJKoZIhvcNAQkEMSIEIELSrGZU YcAr15BZkaqjn18kwgAAlInM97NIPjeBwwPeMGwGCSqGSIb3DQEJDzFfMF0wCwYJYIZIAWUD BAEqMAsGCWCGSAFlAwQBAjAKBggqhkiG9w0DBzAOBggqhkiG9w0DAgICAIAwDQYIKoZIhvcN AwICAUAwBwYFKw4DAgcwDQYIKoZIhvcNAwICASgwgcEGCSsGAQQBgjcQBDGBszCBsDCBmzEL MAkGA1UEBhMCR0IxGzAZBgNVBAgTEkdyZWF0ZXIgTWFuY2hlc3RlcjEQMA4GA1UEBxMHU2Fs Zm9yZDEaMBgGA1UEChMRQ09NT0RPIENBIExpbWl0ZWQxQTA/BgNVBAMTOENPTU9ETyBTSEEt MjU2IENsaWVudCBBdXRoZW50aWNhdGlvbiBhbmQgU2VjdXJlIEVtYWlsIENBAhBzVOU8fWu0 zQ1gaQ38zgEbMIHDBgsqhkiG9w0BCRACCzGBs6CBsDCBmzELMAkGA1UEBhMCR0IxGzAZBgNV BAgTEkdyZWF0ZXIgTWFuY2hlc3RlcjEQMA4GA1UEBxMHU2FsZm9yZDEaMBgGA1UEChMRQ09N T0RPIENBIExpbWl0ZWQxQTA/BgNVBAMTOENPTU9ETyBTSEEtMjU2IENsaWVudCBBdXRoZW50 aWNhdGlvbiBhbmQgU2VjdXJlIEVtYWlsIENBAhBzVOU8fWu0zQ1gaQ38zgEbMA0GCSqGSIb3 DQEBAQUABIIBAGqp5tH7/r9XpxllS5SFPz/FY85Gy/ifPzPHXPmswQiYTokPngEKqsXGbcm7 T6TACrUBjX744G0y3aCYpF6qBfWvbpmZ+L0tDdlB7dExn7nM63FjQalaFezZSvaGuF6Odr4I pqxOX7Z9wY7OrOLpsPZuBuKXRJlBCzrdObXVVo2nw2cCodvCOwkjR30aIqNjdbifHd1WyDLK dGo+qANm6vNxEWoGM+P5JvstNfEmkOFh/6FGO9sR3ev6tzuXThf/Ik7u1Oq3zrxL2aIN09Ea Gm+IHO62SQ8ttKiA56cg8Hp55dZwZNph476hC+KaGf+pPdcbHzTf7phF61BXcfg2mWAAAAAA AAA= --------------ms050809030909050706080009--
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?c749cde5-7329-822d-7ab2-8c65510fbc75>