Date: Sun, 28 Mar 2004 21:21:10 -0600 From: Jay Hall <jhall@vandaliamo.net> To: freebsd-net@freebsd.org Subject: RE: PPTP MTU Message-ID: <40679626.1040104@vandaliamo.net>
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OK, I think I have an MTU negotiation problem. The server side sets an MTU of 1458 and the client side sets an MTU of 1456. Occassionally, the MTUs on the client and the server will be the same and then the connection comes up and runs like a champ as long as the MTU is 1456. Any other values, even if they are the same on the client and server end result in a connection that comes up and then drops. Both the client and the server contain the line set link mtu 1460 In order to use the PPTP connection, I connect to the Internet using a DSL connection. I have tried using both MPD and ppp to establish the Internet connection. And, while the Internet connection is always successful, the pptp connection is not. I am using an Intel 10/100/1000 NIC in the server on the client end. I am using a Westell 2100 DSL modem, in bridge mode, to establish the DSL connection. Is it possible that this is a hardware issue? Thanks for your help. Jay Date: Sat, 27 Mar 2004 08:08:34 -0600 From: Jay Hall <jhall@vandaliamo.net> Subject: PPTP mtu To: freebsd-net@freebsd.org Message-ID: <40658AE2.2080506@vandaliamo.net> Content-Type: text/plain; charset=us-ascii; format=flowed I am using mpd to establish a DSL connection and, once that connection is established, I am brining up a PPTP connection. However, I am having problems keeping the PPTP connection up. In the logs on the remote machine, I am seeing the following error message: Mar 27 00:22:52 ST_CHARLES mpd: [vpn] CCP: rec'd Configure Nak #1 link 0 (Req-Sent) Mar 27 00:22:52 ST_CHARLES mpd: MPPC Mar 27 00:22:52 ST_CHARLES mpd: 0x01000040: MPPE, 128 bit, stateless Mar 27 00:22:52 ST_CHARLES mpd: [vpn] CCP: SendConfigReq #2 Mar 27 00:22:52 ST_CHARLES mpd: MPPC Mar 27 00:22:52 ST_CHARLES mpd: 0x01000040: MPPE, 128 bit, stateless Mar 27 00:22:52 ST_CHARLES mpd: [vpn] error writing len 14 frame to bypass: No route to host Mar 27 00:22:54 ST_CHARLES mpd: [vpn] CCP: rec'd Configure Request #56 link 0 (Req-Sent) Mar 27 00:22:54 ST_CHARLES mpd: MPPC Mar 27 00:22:54 ST_CHARLES mpd: 0x01000060: MPPE, 40 bit, 128 bit, stateless Mar 27 00:22:54 ST_CHARLES mpd: [vpn] CCP: SendConfigNak #56 Mar 27 00:22:54 ST_CHARLES mpd: MPPC Mar 27 00:22:54 ST_CHARLES mpd: 0x01000040: MPPE, 128 bit, stateless Mar 27 00:22:54 ST_CHARLES mpd: [vpn] error writing len 14 frame to bypass: No route to host Mar 27 00:22:54 ST_CHARLES mpd: [vpn] CCP: SendConfigReq #3 Mar 27 00:22:54 ST_CHARLES mpd: MPPC Mar 27 00:22:54 ST_CHARLES mpd: 0x01000040: MPPE, 128 bit, stateless Mar 27 00:22:54 ST_CHARLES mpd: [vpn] error writing len 14 frame to bypass: No route to host Mar 27 00:22:56 ST_CHARLES mpd: [vpn] CCP: rec'd Configure Request #57 link 0 (Req-Sent) Mar 27 00:22:56 ST_CHARLES mpd: MPPC Mar 27 00:22:56 ST_CHARLES mpd: 0x01000060: MPPE, 40 bit, 128 bit, stateless Mar 27 00:22:56 ST_CHARLES mpd: [vpn] CCP: SendConfigNak #57 Mar 27 00:22:56 ST_CHARLES mpd: MPPC Mar 27 00:22:56 ST_CHARLES mpd: 0x01000040: MPPE, 128 bit, stateless Mar 27 00:22:56 ST_CHARLES mpd: [vpn] error writing len 14 frame to bypass: No route to host Mar 27 00:22:56 ST_CHARLES mpd: [vpn] CCP: SendConfigReq #4 Mar 27 00:22:56 ST_CHARLES mpd: MPPC Mar 27 00:22:56 ST_CHARLES mpd: 0x01000040: MPPE, 128 bit, stateless Mar 27 00:22:58 ST_CHARLES mpd: [vpn] CCP: rec'd Configure Request #58 link 0 (Req-Sent) Mar 27 00:22:58 ST_CHARLES mpd: MPPC Mar 27 00:22:58 ST_CHARLES mpd: 0x01000060: MPPE, 40 bit, 128 bit, stateless Mar 27 00:22:58 ST_CHARLES mpd: [vpn] CCP: SendConfigNak #58 Mar 27 00:22:58 ST_CHARLES mpd: MPPC Mar 27 00:22:58 ST_CHARLES mpd: 0x01000040: MPPE, 128 bit, stateless Mar 27 00:22:58 ST_CHARLES mpd: [vpn] CCP: SendConfigReq #5 Mar 27 00:22:58 ST_CHARLES mpd: MPPC Mar 27 00:22:58 ST_CHARLES mpd: 0x01000040: MPPE, 128 bit, stateless Mar 27 00:23:00 ST_CHARLES mpd: [vpn] CCP: rec'd Configure Request #59 link 0 (Req-Sent) Mar 27 00:23:00 ST_CHARLES mpd: MPPC Mar 27 00:23:00 ST_CHARLES mpd: 0x01000060: MPPE, 40 bit, 128 bit, stateless Mar 27 00:23:00 ST_CHARLES mpd: [vpn] CCP: SendConfigNak #59 Mar 27 00:23:00 ST_CHARLES mpd: MPPC Mar 27 00:23:00 ST_CHARLES mpd: 0x01000040: MPPE, 128 bit, stateless Mar 27 00:23:00 ST_CHARLES mpd: [vpn] CCP: SendConfigReq #6 Mar 27 00:23:00 ST_CHARLES mpd: MPPC Mar 27 00:23:00 ST_CHARLES mpd: 0x01000040: MPPE, 128 bit, stateless Mar 27 00:23:02 ST_CHARLES mpd: [vpn] CCP: rec'd Configure Request #60 link 0 (Req-Sent) Mar 27 00:23:02 ST_CHARLES mpd: MPPC Mar 27 00:23:02 ST_CHARLES mpd: 0x01000060: MPPE, 40 bit, 128 bit, stateless Mar 27 00:23:02 ST_CHARLES mpd: [vpn] CCP: SendConfigNak #60 Mar 27 00:23:02 ST_CHARLES mpd: MPPC Mar 27 00:23:02 ST_CHARLES mpd: 0x01000040: MPPE, 128 bit, stateless Mar 27 00:23:02 ST_CHARLES mpd: [vpn] CCP: SendConfigReq #7 Mar 27 00:23:02 ST_CHARLES mpd: MPPC Mar 27 00:23:02 ST_CHARLES mpd: 0x01000040: MPPE, 128 bit, stateless Mar 27 00:23:04 ST_CHARLES mpd: [vpn] CCP: rec'd Configure Request #61 link 0 (Req-Sent) Mar 27 00:23:04 ST_CHARLES mpd: MPPC Mar 27 00:23:04 ST_CHARLES mpd: 0x01000060: MPPE, 40 bit, 128 bit, stateless Mar 27 00:23:04 ST_CHARLES mpd: [vpn] CCP: SendConfigNak #61 Mar 27 00:23:04 ST_CHARLES mpd: MPPC Mar 27 00:23:04 ST_CHARLES mpd: 0x01000040: MPPE, 128 bit, stateless Mar 27 00:23:04 ST_CHARLES mpd: [vpn] CCP: SendConfigReq #8 Mar 27 00:23:04 ST_CHARLES mpd: MPPC Mar 27 00:23:04 ST_CHARLES mpd: 0x01000040: MPPE, 128 bit, stateless Mar 27 00:23:06 ST_CHARLES mpd: [vpn] CCP: SendConfigReq #9 Mar 27 00:23:06 ST_CHARLES mpd: MPPC Mar 27 00:23:06 ST_CHARLES mpd: 0x01000040: MPPE, 128 bit, stateless Mar 27 00:23:08 ST_CHARLES mpd: [vpn] CCP: rec'd Configure Request #63 link 0 (Req-Sent) Mar 27 00:23:08 ST_CHARLES mpd: MPPC Mar 27 00:23:08 ST_CHARLES mpd: 0x01000060: MPPE, 40 bit, 128 bit, stateless Mar 27 00:23:08 ST_CHARLES mpd: [vpn] CCP: not converging Mar 27 00:23:08 ST_CHARLES mpd: [vpn] CCP: parameter negotiation failed Mar 27 00:23:08 ST_CHARLES mpd: [vpn] CCP: Close event Mar 27 00:23:08 ST_CHARLES mpd: [vpn] CCP: state change Req-Sent --> Closing Mar 27 00:23:08 ST_CHARLES mpd: [vpn] CCP: SendTerminateReq #10 Mar 27 00:23:08 ST_CHARLES mpd: [vpn] CCP: encryption required, but MPPE was not negotiated in both directions Mar 27 00:23:08 ST_CHARLES mpd: [vpn] CCP: failed to negotiate required encryption Mar 27 00:23:08 ST_CHARLES mpd: [vpn] CCP: Close event Mar 27 00:23:08 ST_CHARLES mpd: [vpn] CCP: state change Closing --> Closed Mar 27 00:23:08 ST_CHARLES mpd: [vpn] CCP: LayerFinish Mar 27 00:23:08 ST_CHARLES mpd: [vpn] IPCP: failed to negotiate required encryption Mar 27 00:23:08 ST_CHARLES mpd: [vpn] IPCP: LayerFinish Mar 27 00:23:08 ST_CHARLES mpd: [vpn] IPCP: LayerStart On the server I am seeing the following messages: [pptp1] CCP: parameter negotiation failed I think this might be an MTU problem. When the MTU is negotiated at 1456, the connection runs fine. However, at values higher or lower, the connection does not work, and will drop after a few seconds. I am using mpd-3.15 on both ends of the connection. Any suggestions would be greatly appreciated. Thank in advance for your assistance. Jay
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