Discussion:
MPD 3.13 PPTP server MTU problems & questions
(too old to reply)
Yann Nottara
2003-07-16 18:33:55 UTC
Permalink
Hello,

I've been running a FreeBSD 4.7 box with a MPD 3.13 PPTP VPN server for
quite some time now and, altough it mostly works, I'd like to iron out
some problems we encounter.

Configuration (that gives an IP address in a 192.168.0.0/24 local
network to 16 Win2k clients at this moment) is done according to the
following model :

MPD PPTP, DNS & Samba server is 192.168.0.10

mpd.conf
*****************************************
default:
load pptp0

pptp0:
new -i ng0 pptp0 pptp0
set iface route 192.168.0.10/24
set iface disable on-demand
set iface enable proxy-arp
set iface idle 3600
set bundle enable multilink
set link yes acfcomp protocomp
set link no pap chap
set link enable chap
set link keep-alive 10 60
set link mtu 1460
set ipcp yes vjcomp
set ipcp ranges 192.168.0.10/32 192.168.0.204/32
set ipcp dns 192.168.0.10
set ipcp nbns 192.168.0.10
set bundle enable compression
set ccp yes mppc
set ccp no mpp-e40
set ccp yes mpp-e128
set ccp yes mpp-stateless

******************************************


mpd.links
******************************************
pptp0:
set link type pptp
set pptp self 192.168.0.10
set pptp enable incoming
set pptp disable originate
******************************************


As you'll see in the logs below and from ifconfig output, altough the
ngX interfaces MTU is set to 1460 with "set link mtu 1460", it stays at
1500. Any idea why ?


***************************************
***@bull ~ $ ifconfig
fxp0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
inet 192.168.0.10 netmask 0xffffff00 broadcast 192.168.0.255
inet6 fe80::2b0:d0ff:fee1:4874%fxp0 prefixlen 64 scopeid 0x1
ether 00:b0:d0:e1:48:74
media: Ethernet autoselect (100baseTX <full-duplex>)
status: active
fxp1: flags=8802<BROADCAST,SIMPLEX,MULTICAST> mtu 1500
ether 00:b0:d0:e1:48:75
media: Ethernet autoselect (none)
status: no carrier
lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> mtu 16384
inet6 ::1 prefixlen 128
inet6 fe80::1%lo0 prefixlen 64 scopeid 0x3
inet 127.0.0.1 netmask 0xff000000
ppp0: flags=8010<POINTOPOINT,MULTICAST> mtu 1500
sl0: flags=c010<POINTOPOINT,LINK2,MULTICAST> mtu 552
faith0: flags=8002<BROADCAST,MULTICAST> mtu 1500
ng0: flags=88d1<UP,POINTOPOINT,RUNNING,NOARP,SIMPLEX,MULTICAST> mtu 1500
inet6 fe80::2b0:d0ff:fee1:4874%ng0 prefixlen 64 scopeid 0x7
inet 192.168.0.10 --> 192.168.0.204 netmask 0xffffffff
ng1: flags=8890<POINTOPOINT,NOARP,SIMPLEX,MULTICAST> mtu 1500
inet6 fe80::2b0:d0ff:fee1:4874%ng1 prefixlen 64 scopeid 0x8
ng2: flags=8890<POINTOPOINT,NOARP,SIMPLEX,MULTICAST> mtu 1500
inet6 fe80::2b0:d0ff:fee1:4874%ng2 prefixlen 64 scopeid 0x9
ng3: flags=8890<POINTOPOINT,NOARP,SIMPLEX,MULTICAST> mtu 1500
inet6 fe80::2b0:d0ff:fee1:4874%ng3 prefixlen 64 scopeid 0xa
ng4: flags=8890<POINTOPOINT,NOARP,SIMPLEX,MULTICAST> mtu 1500
inet6 fe80::2b0:d0ff:fee1:4874%ng4 prefixlen 64 scopeid 0xb
ng5: flags=8890<POINTOPOINT,NOARP,SIMPLEX,MULTICAST> mtu 1500
ng6: flags=8890<POINTOPOINT,NOARP,SIMPLEX,MULTICAST> mtu 1500
ng7: flags=8890<POINTOPOINT,NOARP,SIMPLEX,MULTICAST> mtu 1500
ng8: flags=8890<POINTOPOINT,NOARP,SIMPLEX,MULTICAST> mtu 1500
ng9: flags=8890<POINTOPOINT,NOARP,SIMPLEX,MULTICAST> mtu 1500
ng10: flags=8890<POINTOPOINT,NOARP,SIMPLEX,MULTICAST> mtu 1500
ng11: flags=8890<POINTOPOINT,NOARP,SIMPLEX,MULTICAST> mtu 1500
ng12: flags=8890<POINTOPOINT,NOARP,SIMPLEX,MULTICAST> mtu 1500
ng13: flags=8890<POINTOPOINT,NOARP,SIMPLEX,MULTICAST> mtu 1500
ng14: flags=8890<POINTOPOINT,NOARP,SIMPLEX,MULTICAST> mtu 1500
ng15: flags=8890<POINTOPOINT,NOARP,SIMPLEX,MULTICAST> mtu 1500
ng16: flags=8890<POINTOPOINT,NOARP,SIMPLEX,MULTICAST> mtu 1500


mpd.log
*******************************************
Jul 16 18:52:11 bull mpd: mpd: PPTP connection from 123.456.789.12:25833
Jul 16 18:52:11 bull mpd: pptp0: attached to connection with
123.456.789.12:25833
Jul 16 18:52:11 bull mpd: [pptp0] IFACE: Open event
Jul 16 18:52:11 bull mpd: [pptp0] IPCP: Open event
Jul 16 18:52:11 bull mpd: [pptp0] IPCP: state change Initial --> Starting
Jul 16 18:52:11 bull mpd: [pptp0] IPCP: LayerStart
Jul 16 18:52:11 bull mpd: [pptp0] IPCP: Open event
Jul 16 18:52:11 bull mpd: [pptp0] bundle: OPEN event in state CLOSED
Jul 16 18:52:11 bull mpd: [pptp0] opening link "pptp0"...
Jul 16 18:52:11 bull mpd: [pptp0] link: OPEN event
Jul 16 18:52:11 bull mpd: [pptp0] LCP: Open event
Jul 16 18:52:11 bull mpd: [pptp0] LCP: state change Initial --> Starting
Jul 16 18:52:11 bull mpd: [pptp0] LCP: LayerStart
Jul 16 18:52:11 bull mpd: [pptp0] device: OPEN event in state DOWN
Jul 16 18:52:11 bull mpd: [pptp0] attaching to peer's outgoing call
Jul 16 18:52:11 bull mpd: [pptp0] device is now in state OPENING
Jul 16 18:52:11 bull mpd: [pptp0] device: UP event in state OPENING
Jul 16 18:52:11 bull mpd: [pptp0] device is now in state UP
Jul 16 18:52:11 bull mpd: [pptp0] link: UP event
Jul 16 18:52:11 bull mpd: [pptp0] link: origination is remote
Jul 16 18:52:11 bull mpd: [pptp0] LCP: Up event
Jul 16 18:52:11 bull mpd: [pptp0] LCP: state change Starting --> Req-Sent
Jul 16 18:52:11 bull mpd: [pptp0] LCP: phase shift DEAD --> ESTABLISH
Jul 16 18:52:11 bull mpd: [pptp0] LCP: SendConfigReq #198
Jul 16 18:52:11 bull mpd: ACFCOMP
Jul 16 18:52:11 bull mpd: PROTOCOMP
Jul 16 18:52:11 bull mpd: MRU 1500
Jul 16 18:52:11 bull mpd: MAGICNUM e7805d68
Jul 16 18:52:11 bull mpd: AUTHPROTO CHAP MSOFTv2
Jul 16 18:52:11 bull mpd: MP MRRU 1600
Jul 16 18:52:11 bull mpd: MP SHORTSEQ
Jul 16 18:52:11 bull mpd: ENDPOINTDISC [802.1] 00 b0 d0 e1 48 74
Jul 16 18:52:11 bull mpd: pptp0-0: ignoring SetLinkInfo
Jul 16 18:52:11 bull mpd: [pptp0] LCP: rec'd Configure Request #0 link 0
(Req-Sent)
Jul 16 18:52:11 bull mpd: MAGICNUM 278a44ec
Jul 16 18:52:11 bull mpd: PROTOCOMP
Jul 16 18:52:11 bull mpd: ACFCOMP
Jul 16 18:52:11 bull mpd: CALLBACK
Jul 16 18:52:11 bull mpd: Not supported
Jul 16 18:52:11 bull mpd: MP MRRU 1614
Jul 16 18:52:11 bull mpd: ENDPOINTDISC [LOCAL] a6 92 ca 2c f4 8b 47 51
b5 e1 9d da b3 7b 7b 3e 00 00 00 06
Jul 16 18:52:11 bull mpd: [pptp0] LCP: SendConfigRej #0
Jul 16 18:52:11 bull mpd: CALLBACK
Jul 16 18:52:11 bull mpd: [pptp0] LCP: rec'd Configure Reject #198 link
0 (Req-Sent)
Jul 16 18:52:11 bull mpd: MP SHORTSEQ
Jul 16 18:52:11 bull mpd: [pptp0] LCP: SendConfigReq #199
Jul 16 18:52:11 bull mpd: ACFCOMP
Jul 16 18:52:11 bull mpd: PROTOCOMP
Jul 16 18:52:11 bull mpd: MRU 1500
Jul 16 18:52:11 bull mpd: MAGICNUM e7805d68
Jul 16 18:52:11 bull mpd: AUTHPROTO CHAP MSOFTv2
Jul 16 18:52:11 bull mpd: MP MRRU 1600
Jul 16 18:52:11 bull mpd: ENDPOINTDISC [802.1] 00 b0 d0 e1 48 74
Jul 16 18:52:11 bull mpd: [pptp0] LCP: rec'd Configure Request #1 link 0
(Req-Sent)
Jul 16 18:52:11 bull mpd: MAGICNUM 278a44ec
Jul 16 18:52:11 bull mpd: PROTOCOMP
Jul 16 18:52:11 bull mpd: ACFCOMP
Jul 16 18:52:11 bull mpd: MP MRRU 1614
Jul 16 18:52:11 bull mpd: ENDPOINTDISC [LOCAL] a6 92 ca 2c f4 8b 47 51
b5 e1 9d da b3 7b 7b 3e 00 00 00 06
Jul 16 18:52:11 bull mpd: [pptp0] LCP: SendConfigNak #1
Jul 16 18:52:11 bull mpd: ENDPOINTDISC [LOCAL] a6 92 ca 2c f4 8b 47 51
b5 e1 9d da b3 7b 7b 3e 00 00 00 06
Jul 16 18:52:11 bull mpd: [pptp0] LCP: SendConfigNak #1
Jul 16 18:52:11 bull mpd: MP MRRU 1600
Jul 16 18:52:11 bull mpd: [pptp0] LCP: rec'd Configure Ack #199 link 0
(Req-Sent)
Jul 16 18:52:11 bull mpd: ACFCOMP
Jul 16 18:52:11 bull mpd: PROTOCOMP
Jul 16 18:52:11 bull mpd: MRU 1500
Jul 16 18:52:11 bull mpd: MAGICNUM e7805d68
Jul 16 18:52:11 bull mpd: AUTHPROTO CHAP MSOFTv2
Jul 16 18:52:11 bull mpd: MP MRRU 1600
Jul 16 18:52:11 bull mpd: ENDPOINTDISC [802.1] 00 b0 d0 e1 48 74
Jul 16 18:52:11 bull mpd: [pptp0] LCP: state change Req-Sent --> Ack-Rcvd
Jul 16 18:52:11 bull mpd: [pptp0] LCP: rec'd Configure Request #2 link 0
(Ack-Rcvd)
Jul 16 18:52:11 bull mpd: MAGICNUM 278a44ec
Jul 16 18:52:11 bull mpd: PROTOCOMP
Jul 16 18:52:11 bull mpd: ACFCOMP
Jul 16 18:52:11 bull mpd: MP MRRU 1600
Jul 16 18:52:11 bull mpd: ENDPOINTDISC [LOCAL] a6 92 ca 2c f4 8b 47 51
b5 e1 9d da b3 7b 7b 3e 00 00 00 06
Jul 16 18:52:11 bull mpd: [pptp0] LCP: SendConfigAck #2
Jul 16 18:52:11 bull mpd: MAGICNUM 278a44ec
Jul 16 18:52:11 bull mpd: PROTOCOMP
Jul 16 18:52:11 bull mpd: ACFCOMP
Jul 16 18:52:11 bull mpd: MP MRRU 1600
Jul 16 18:52:11 bull mpd: ENDPOINTDISC [LOCAL] a6 92 ca 2c f4 8b 47 51
b5 e1 9d da b3 7b 7b 3e 00 00 00 06
Jul 16 18:52:11 bull mpd: [pptp0] LCP: state change Ack-Rcvd --> Opened
Jul 16 18:52:11 bull mpd: [pptp0] LCP: phase shift ESTABLISH -->
AUTHENTICATE
Jul 16 18:52:11 bull mpd: [pptp0] LCP: auth: peer wants nothing, I want CHAP
Jul 16 18:52:11 bull mpd: [pptp0] CHAP: sending CHALLENGE
Jul 16 18:52:11 bull mpd: [pptp0] LCP: LayerUp
Jul 16 18:52:11 bull mpd: [pptp0] LCP: rec'd Ident #3 link 0 (Opened)
Jul 16 18:52:11 bull mpd: MESG: MSRASV5.00
Jul 16 18:52:11 bull mpd: pptp0-0: ignoring SetLinkInfo
Jul 16 18:52:11 bull mpd: [pptp0] LCP: rec'd Ident #4 link 0 (Opened)
Jul 16 18:52:11 bull mpd: MESG: MSRAS-1-HINANO
Jul 16 18:52:11 bull mpd: [pptp0] CHAP: rec'd RESPONSE #1
Jul 16 18:52:11 bull mpd: Name: "xxxx"
Jul 16 18:52:11 bull mpd: Peer name: "xxxx"
Jul 16 18:52:11 bull mpd: Response is valid
Jul 16 18:52:11 bull mpd: [pptp0] CHAP: sending SUCCESS
Jul 16 18:52:11 bull mpd: [pptp0] LCP: authorization successful
Jul 16 18:52:11 bull mpd: [pptp0] LCP: phase shift AUTHENTICATE --> NETWORK
Jul 16 18:52:11 bull mpd: [pptp0] setting interface ng0 MTU to 1500 bytes
Jul 16 18:52:11 bull mpd: [pptp0] up: 1 link, total bandwidth 64000 bps
Jul 16 18:52:11 bull mpd: [pptp0] IPCP: Up event
Jul 16 18:52:11 bull mpd: [pptp0] IPCP: state change Starting --> Req-Sent
Jul 16 18:52:11 bull mpd: [pptp0] IPCP: SendConfigReq #203
Jul 16 18:52:11 bull mpd: IPADDR 192.168.0.10
Jul 16 18:52:11 bull mpd: COMPPROTO VJCOMP, 16 comp. channels, no comp-cid
Jul 16 18:52:11 bull mpd: [pptp0] error writing len 20 frame to bypass:
Network is down
Jul 16 18:52:11 bull mpd: [pptp0] CCP: Open event
Jul 16 18:52:11 bull mpd: [pptp0] CCP: state change Initial --> Starting
Jul 16 18:52:11 bull mpd: [pptp0] CCP: LayerStart
Jul 16 18:52:11 bull mpd: [pptp0] CCP: Up event
Jul 16 18:52:11 bull mpd: [pptp0] CCP: state change Starting --> Req-Sent
Jul 16 18:52:11 bull mpd: [pptp0] CCP: SendConfigReq #118
Jul 16 18:52:11 bull mpd: MPPC
Jul 16 18:52:11 bull mpd: 0x01000040: MPPE, 128 bit, stateless
Jul 16 18:52:11 bull mpd: [pptp0] error writing len 14 frame to bypass:
Network is down
Jul 16 18:52:11 bull mpd: [pptp0] CCP: rec'd Configure Request #5 link 0
(Req-Sent)
Jul 16 18:52:11 bull mpd: MPPC
Jul 16 18:52:11 bull mpd: [pptp0] CCP: rec'd Configure Request #5 link 0
(Req-Sent)
Jul 16 18:52:11 bull mpd: MPPC
Jul 16 18:52:11 bull mpd: 0x01000041: MPPC MPPE, 128 bit, stateless
Jul 16 18:52:11 bull mpd: [pptp0] CCP: SendConfigNak #5
Jul 16 18:52:11 bull mpd: MPPC
Jul 16 18:52:11 bull mpd: 0x01000040: MPPE, 128 bit, stateless
Jul 16 18:52:11 bull mpd: [pptp0] IPCP: rec'd Configure Request #6 link
0 (Req-Sent)
Jul 16 18:52:11 bull mpd: IPADDR 0.0.0.0
Jul 16 18:52:11 bull mpd: NAKing with 192.168.0.204
Jul 16 18:52:11 bull mpd: PRIDNS 0.0.0.0
Jul 16 18:52:11 bull mpd: NAKing with 192.168.0.10
Jul 16 18:52:11 bull mpd: PRINBNS 0.0.0.0
Jul 16 18:52:11 bull mpd: NAKing with 192.168.0.10
Jul 16 18:52:11 bull mpd: SECDNS 0.0.0.0
Jul 16 18:52:11 bull mpd: SECNBNS 0.0.0.0
Jul 16 18:52:11 bull mpd: [pptp0] IPCP: SendConfigRej #6
Jul 16 18:52:11 bull mpd: SECDNS 0.0.0.0
Jul 16 18:52:11 bull mpd: SECNBNS 0.0.0.0
Jul 16 18:52:11 bull mpd: [pptp0] CCP: rec'd Configure Request #7 link 0
(Req-Sent)
Jul 16 18:52:11 bull mpd: MPPC
Jul 16 18:52:11 bull mpd: 0x01000040: MPPE, 128 bit, stateless
Jul 16 18:52:11 bull mpd: [pptp0] CCP: SendConfigAck #7
Jul 16 18:52:11 bull mpd: MPPC
Jul 16 18:52:11 bull mpd: 0x01000040: MPPE, 128 bit, stateless
Jul 16 18:52:11 bull mpd: [pptp0] CCP: state change Req-Sent --> Ack-Sent
Jul 16 18:52:11 bull mpd: [pptp0] IPCP: rec'd Configure Request #8 link
0 (Req-Sent)
Jul 16 18:52:11 bull mpd: IPADDR 0.0.0.0
Jul 16 18:52:11 bull mpd: NAKing with 192.168.0.204
Jul 16 18:52:11 bull mpd: PRIDNS 0.0.0.0
Jul 16 18:52:11 bull mpd: NAKing with 192.168.0.10
Jul 16 18:52:11 bull mpd: PRINBNS 0.0.0.0
Jul 16 18:52:11 bull mpd: NAKing with 192.168.0.10
Jul 16 18:52:11 bull mpd: [pptp0] IPCP: SendConfigNak #8
Jul 16 18:52:11 bull mpd: IPADDR 192.168.0.204
Jul 16 18:52:11 bull mpd: PRIDNS 192.168.0.10
Jul 16 18:52:11 bull mpd: PRINBNS 192.168.0.10
Jul 16 18:52:11 bull mpd: [pptp0] IPCP: rec'd Configure Request #9 link
0 (Req-Sent)
Jul 16 18:52:11 bull mpd: IPADDR 192.168.0.204
Jul 16 18:52:11 bull mpd: 192.168.0.204 is OK
Jul 16 18:52:11 bull mpd: PRIDNS 192.168.0.10
Jul 16 18:52:11 bull mpd: PRINBNS 192.168.0.10
Jul 16 18:52:11 bull mpd: [pptp0] IPCP: SendConfigAck #9
Jul 16 18:52:11 bull mpd: IPADDR 192.168.0.204
Jul 16 18:52:11 bull mpd: PRIDNS 192.168.0.10
Jul 16 18:52:11 bull mpd: PRINBNS 192.168.0.10
Jul 16 18:52:11 bull mpd: [pptp0] IPCP: state change Req-Sent --> Ack-Sent
Jul 16 18:52:13 bull mpd: [pptp0] IPCP: SendConfigReq #204
Jul 16 18:52:13 bull mpd: IPADDR 192.168.0.10
Jul 16 18:52:13 bull mpd: COMPPROTO VJCOMP, 16 comp. channels, no comp-cid
Jul 16 18:52:13 bull mpd: [pptp0] CCP: SendConfigReq #119
Jul 16 18:52:13 bull mpd: MPPC
Jul 16 18:52:13 bull mpd: 0x01000040: MPPE, 128 bit, stateless
Jul 16 18:52:13 bull mpd: [pptp0] IPCP: rec'd Configure Reject #204 link
0 (Ack-Sent)
Jul 16 18:52:13 bull mpd: COMPPROTO VJCOMP, 16 comp. channels, no comp-cid
Jul 16 18:52:13 bull mpd: [pptp0] IPCP: SendConfigReq #205
Jul 16 18:52:13 bull mpd: IPADDR 192.168.0.10
Jul 16 18:52:13 bull mpd: [pptp0] CCP: rec'd Configure Ack #119 link 0
(Ack-Sent)
Jul 16 18:52:13 bull mpd: MPPC
Jul 16 18:52:13 bull mpd: 0x01000040: MPPE, 128 bit, stateless
Jul 16 18:52:13 bull mpd: [pptp0] CCP: state change Ack-Sent --> Opened
Jul 16 18:52:11 bull mpd: [pptp0] CCP: rec'd Configure Request #7 link 0
(Req-Sent)
Jul 16 18:52:11 bull mpd: MPPC
Jul 16 18:52:11 bull mpd: 0x01000040: MPPE, 128 bit, stateless
Jul 16 18:52:11 bull mpd: [pptp0] CCP: SendConfigAck #7
Jul 16 18:52:11 bull mpd: MPPC
Jul 16 18:52:11 bull mpd: 0x01000040: MPPE, 128 bit, stateless
Jul 16 18:52:11 bull mpd: [pptp0] CCP: state change Req-Sent --> Ack-Sent
Jul 16 18:52:11 bull mpd: [pptp0] IPCP: rec'd Configure Request #8 link
0 (Req-Sent)
Jul 16 18:52:11 bull mpd: IPADDR 0.0.0.0
Jul 16 18:52:11 bull mpd: NAKing with 192.168.0.204
Jul 16 18:52:11 bull mpd: PRIDNS 0.0.0.0
Jul 16 18:52:11 bull mpd: NAKing with 192.168.0.10
Jul 16 18:52:11 bull mpd: PRINBNS 0.0.0.0
Jul 16 18:52:11 bull mpd: NAKing with 192.168.0.10
Jul 16 18:52:11 bull mpd: [pptp0] IPCP: SendConfigNak #8
Jul 16 18:52:11 bull mpd: IPADDR 192.168.0.204
Jul 16 18:52:11 bull mpd: PRIDNS 192.168.0.10
Jul 16 18:52:11 bull mpd: PRINBNS 192.168.0.10
Jul 16 18:52:11 bull mpd: [pptp0] IPCP: rec'd Configure Request #9 link
0 (Req-Sent)
Jul 16 18:52:11 bull mpd: IPADDR 192.168.0.204
Jul 16 18:52:11 bull mpd: 192.168.0.204 is OK
Jul 16 18:52:11 bull mpd: PRIDNS 192.168.0.10
Jul 16 18:52:11 bull mpd: PRINBNS 192.168.0.10
Jul 16 18:52:11 bull mpd: [pptp0] IPCP: SendConfigAck #9
Jul 16 18:52:11 bull mpd: IPADDR 192.168.0.204
Jul 16 18:52:11 bull mpd: PRIDNS 192.168.0.10
Jul 16 18:52:11 bull mpd: PRINBNS 192.168.0.10
Jul 16 18:52:11 bull mpd: [pptp0] IPCP: state change Req-Sent --> Ack-Sent
Jul 16 18:52:13 bull mpd: [pptp0] IPCP: SendConfigReq #204
Jul 16 18:52:13 bull mpd: IPADDR 192.168.0.10
Jul 16 18:52:13 bull mpd: COMPPROTO VJCOMP, 16 comp. channels, no comp-cid
Jul 16 18:52:13 bull mpd: [pptp0] CCP: SendConfigReq #119
Jul 16 18:52:13 bull mpd: MPPC
Jul 16 18:52:13 bull mpd: 0x01000040: MPPE, 128 bit, stateless
Jul 16 18:52:13 bull mpd: [pptp0] IPCP: rec'd Configure Reject #204 link
0 (Ack-Sent)
Jul 16 18:52:13 bull mpd: COMPPROTO VJCOMP, 16 comp. channels, no comp-cid
Jul 16 18:52:13 bull mpd: [pptp0] IPCP: SendConfigReq #205
Jul 16 18:52:13 bull mpd: IPADDR 192.168.0.10
Jul 16 18:52:13 bull mpd: [pptp0] CCP: rec'd Configure Ack #119 link 0
(Ack-Sent)
Jul 16 18:52:13 bull mpd: MPPC
Jul 16 18:52:13 bull mpd: 0x01000040: MPPE, 128 bit, stateless
Jul 16 18:52:13 bull mpd: [pptp0] CCP: state change Ack-Sent --> Opened
Jul 16 18:52:13 bull mpd: [pptp0] CCP: LayerUp
Jul 16 18:52:13 bull mpd: Compress using: MPPE, 128 bit, stateless
Jul 16 18:52:13 bull mpd: Decompress using: MPPE, 128 bit, stateless
Jul 16 18:52:13 bull mpd: [pptp0] setting interface ng0 MTU to 1500 bytes
Jul 16 18:52:13 bull mpd: [pptp0] IPCP: rec'd Configure Ack #205 link 0
(Ack-Sent)
Jul 16 18:52:13 bull mpd: IPADDR 192.168.0.10
Jul 16 18:52:13 bull mpd: [pptp0] IPCP: state change Ack-Sent --> Opened
Jul 16 18:52:13 bull mpd: [pptp0] IPCP: LayerUp
Jul 16 18:52:13 bull mpd: 192.168.0.10 -> 192.168.0.204
Jul 16 18:52:13 bull mpd: [pptp0] IFACE: Up event
Jul 16 18:52:13 bull mpd: [pptp0] setting interface ng0 MTU to 1500 bytes
Jul 16 18:52:13 bull mpd: [pptp0] exec: /sbin/ifconfig ng0 192.168.0.10
192.168.0.204 netmask 0xffffffff -link0
Jul 16 18:52:13 bull mpd: [pptp0] exec: /usr/sbin/arp -s 192.168.0.204
0:b0:d0:e1:48:74 pub
Jul 16 18:52:13 bull mpd: [pptp0] exec: /sbin/route add 192.168.0.10
-iface lo0
Jul 16 18:52:13 bull mpd: [pptp0] exec: /sbin/route add 192.168.0.0
192.168.0.204 -netmask 0xffffff00
Jul 16 18:52:13 bull mpd: [pptp0] exec: command returned 256
Jul 16 18:52:13 bull mpd: [pptp0] IFACE: Up event
Jul 16 18:52:13 bull mpd: [pptp0] rec'd unexpected protocol IP on link -1


My other problem (maybe related to the previous one ?) is SMB browsing :
PPTP clients connected through the VPN can see but not browse all the
other machines on the local network. The only one that can be browsed is
the one also hosting the PPTP server : routing problem ?


By the way, is there a way to reduce mpd's log verbosity ?


Thanks for your time & help.

Regards,

--Yann
Yann Nottara
2003-07-17 16:40:22 UTC
Permalink
| As you'll see in the logs below and from ifconfig output, altough the
| ngX interfaces MTU is set to 1460 with "set link mtu 1460", it stays at
| 1500. Any idea why ?
The asked mtu size will be available (set) only when interface is in UP
state. When the ngX is in down state it has default values.
Thanks for your help.

Zs you can see in the following real world example, ng0 (which IS up)
MTU stays at 1500 although it's configured to be at 1460 in the mpd.conf
configuration file :

ng0: flags=8890<POINTOPOINT,NOARP,SIMPLEX,MULTICAST> mtu 1500
inet6 fe80::2b0:d0ff:fee1:4874%ng0 prefixlen 64 scopeid 0x7
ng1: flags=8890<POINTOPOINT,NOARP,SIMPLEX,MULTICAST> mtu 1500
ng2: flags=8890<POINTOPOINT,NOARP,SIMPLEX,MULTICAST> mtu 1500
ng3: flags=8890<POINTOPOINT,NOARP,SIMPLEX,MULTICAST> mtu 1500
...

Any idea ?

--Yann
Yann Nottara
2003-07-17 17:52:27 UTC
Permalink
----- Original Message -----
Post by Yann Nottara
Zs you can see in the following real world example, ng0 (which IS up)
MTU stays at 1500 although it's configured to be at 1460 in the mpd.conf
ng0: flags=8890<POINTOPOINT,NOARP,SIMPLEX,MULTICAST> mtu 1500
inet6 fe80::2b0:d0ff:fee1:4874%ng0 prefixlen 64 scopeid 0x7
This doesn't look UP to me :)
[...]
Whenever MPD receives a connection, and assigns that interface to a
client, it will change the MTU and mark it as UP.
At least, it does for me...
ng0: flags=8890<POINTOPOINT,NOARP,SIMPLEX,MULTICAST> mtu 1500
inet6 fe80::209:5bff:fe2f:692c%ng0 prefixlen 64 scopeid 0x7
ng0: flags=88d1<UP,POINTOPOINT,RUNNING,NOARP,SIMPLEX,MULTICAST> mtu 1396
inet 192.168.0.1 --> 192.168.0.2 netmask 0xffffffff
inet6 fe80::209:5bff:fe2f:692c%ng0 prefixlen 64 scopeid 0x7
Regards,
-Andy
Ok, my mistake on this one :)

but now, what do you think of this ?

ng0: flags=88d1<UP,POINTOPOINT,RUNNING,NOARP,SIMPLEX,MULTICAST> mtu 1500
inet6 fe80::2b0:d0ff:fee1:4874%ng0 prefixlen 64 scopeid 0x7
inet 192.168.0.10 --> 192.168.0.200 netmask 0xffffffff

and here's the part from my mpd.conf that's related to this connection :

pptp0:
new -i ng0 pptp0 pptp0
set iface disable on-demand
set iface enable proxy-arp
set iface idle 3600
set bundle enable multilink
set link yes acfcomp protocomp
set link no pap chap
set link enable chap
set link keep-alive 10 60
set link mtu 1460 <----------------- !
set ipcp yes vjcomp
set ipcp ranges 192.168.0.10/32 192.168.0.200/32
set ipcp dns 192.168.0.10
set ipcp nbns 192.168.0.10

So, where's the catch ?

--Yann
Andy Gilligan
2003-07-17 20:25:49 UTC
Permalink
----- Original Message -----
From: "Yann Nottara" <***@almonde.com>
To: <freebsd-***@freebsd.org>
Sent: Thursday, July 17, 2003 6:53 PM
Subject: Re: MPD 3.13 PPTP server MTU problems & questions
Post by Yann Nottara
but now, what do you think of this ?
ng0: flags=88d1<UP,POINTOPOINT,RUNNING,NOARP,SIMPLEX,MULTICAST> mtu 1500
inet6 fe80::2b0:d0ff:fee1:4874%ng0 prefixlen 64 scopeid 0x7
inet 192.168.0.10 --> 192.168.0.200 netmask 0xffffffff
new -i ng0 pptp0 pptp0
set iface disable on-demand
set iface enable proxy-arp
set iface idle 3600
set bundle enable multilink
set link yes acfcomp protocomp
set link no pap chap
set link enable chap
set link keep-alive 10 60
set link mtu 1460 <----------------- !
set ipcp yes vjcomp
set ipcp ranges 192.168.0.10/32 192.168.0.200/32
set ipcp dns 192.168.0.10
set ipcp nbns 192.168.0.10
So, where's the catch ?
Pretty much the same config as myself, with the exeption that I have:

set bundle enable compression
set ccp yes mppc
set ccp yes mpp-e40
set ccp yes mpp-e128
set ccp yes mpp-stateless

I've set the MTU to 1460 - as you have, which seems to give me 1396
when a client connects.

So far, I've only tested this with Windows XP machines, so I'm not sure
if anything OS-specific concerning the MTU is negotiated during the
connect phase, or even if having MPPE enabled would affect it.

I imagine you've tried setting the MTU to other values?

Best regards,
-Andy
Archie Cobbs
2003-07-18 03:15:27 UTC
Permalink
Post by Yann Nottara
but now, what do you think of this ?
ng0: flags=88d1<UP,POINTOPOINT,RUNNING,NOARP,SIMPLEX,MULTICAST> mtu 1500
inet6 fe80::2b0:d0ff:fee1:4874%ng0 prefixlen 64 scopeid 0x7
inet 192.168.0.10 --> 192.168.0.200 netmask 0xffffffff
new -i ng0 pptp0 pptp0
set iface disable on-demand
set iface enable proxy-arp
set iface idle 3600
set bundle enable multilink
set link yes acfcomp protocomp
set link no pap chap
set link enable chap
set link keep-alive 10 60
set link mtu 1460 <----------------- !
set ipcp yes vjcomp
set ipcp ranges 192.168.0.10/32 192.168.0.200/32
set ipcp dns 192.168.0.10
set ipcp nbns 192.168.0.10
So, where's the catch ?
If what you want is to set a hard limit then "set iface mtu 1460"
is the command to use. "set link mtu" just initializes the starting
value for LCP negotiation.

-Archie

__________________________________________________________________________
Archie Cobbs * Halloo Communications * http://www.halloo.com
Yann Nottara
2003-07-18 09:06:06 UTC
Permalink
----- Original Message -----
Sent: Thursday, July 17, 2003 6:53 PM
Subject: Re: MPD 3.13 PPTP server MTU problems & questions
Post by Yann Nottara
but now, what do you think of this ?
ng0: flags=88d1<UP,POINTOPOINT,RUNNING,NOARP,SIMPLEX,MULTICAST> mtu 1500
inet6 fe80::2b0:d0ff:fee1:4874%ng0 prefixlen 64 scopeid 0x7
inet 192.168.0.10 --> 192.168.0.200 netmask 0xffffffff
new -i ng0 pptp0 pptp0
set iface disable on-demand
set iface enable proxy-arp
set iface idle 3600
set bundle enable multilink
set link yes acfcomp protocomp
set link no pap chap
set link enable chap
set link keep-alive 10 60
set link mtu 1460 <----------------- !
set ipcp yes vjcomp
set ipcp ranges 192.168.0.10/32 192.168.0.200/32
set ipcp dns 192.168.0.10
set ipcp nbns 192.168.0.10
So, where's the catch ?
set bundle enable compression
set ccp yes mppc
set ccp yes mpp-e40
set ccp yes mpp-e128
set ccp yes mpp-stateless
Sorry, I forgot to include that part but I use it too.
I've set the MTU to 1460 - as you have, which seems to give me 1396
when a client connects.
So far, I've only tested this with Windows XP machines, so I'm not sure
if anything OS-specific concerning the MTU is negotiated during the
connect phase, or even if having MPPE enabled would affect it.
My PPTP clients are all Windows 2000 machines.
I imagine you've tried setting the MTU to other values?
Right, and it's all the same (but now I understand why after reading a
post from this thread by Archie Cobbs.
Best regards,
-Andy
Thanks for you help & comments.

--Yann

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