Date: Thu, 7 Dec 2000 13:12:00 -0500 From: "Patrick Bihan-Faou" <patrick@netzuno.com> To: <freebsd-net@freebsd.org> Subject: Problem with PPP, tcpmssd and routing socket messages Message-ID: <POEDLEGGIEKJJIOGHEJNAEINCDAA.patrick@netzuno.com>
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Hi, I am playing around with tcpmssd and an ADSL link. I use tcpmssd with the "-i" option to indicate which interface it should obtain the MTU information from. With this option, tcpmssd starts listening to the routing socket and updates its knowledge of the MTU based on the information received from the routing socket. The problem is that tcpmssd is started before the ppp negotiation is finished, so the initial MTU information is "incorrect" (1500). When the PPP negotiation is done, the MTU for the tun0 interface is updated to the correct value (1492) (as shown in ifconfig), but tcpmssd never receives any notification of that fact. The only routing update related to the tun0 interface that is received by tcpmssd is the "NEWADDR" message indicating the negotiated IP address, I do not see any IFINFO messages (which are the ones used for the MTU updates). If I update the MTU manually (using ifconfig), everything works fine: tcpmssd receives the RTM_IFINFO messages and the new MTU is used. Am I missing something ? Is the routing socket supposed to be "reliable" or can some messages get lost ? Does the fact that multiple processes are listening on the routing socket (natd etc.) changes the behaviour ? I am a bit lost here, I looked at the ppp code and the kernel code that does the MTU updates and the way I understand it, there should always be a routing message generated, however I can not see it anywhere... Patrick. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message
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