PPTP: Добавление ip адреса на интерфейс

freebsd 4.9
ip 10.10.6.162, gw 10.10.6.1, server vpn 172.16.1.38

поставил из портов pptpclient

/etc/ppp/ppp.conf
vpn:
set authname "user"
set authkey "pass"
set timeout 0
set ifaddr 0 0
add default HISADDR

netstat -rn содержит такие строки
default            10.10.6.1          UGSc
172.16.1.38         10.10.6.1          UGHS

/usr/local/sbin/pptp 172.16.1.38 vpn &

cat /var/log/ppp.log
Oct  3 21:51:55 bsd49 ppp[23743]: Phase: Using interface: tun0
Oct  3 21:51:55 bsd49 ppp[23743]: Phase: deflink: Created in closed state
Oct  3 21:51:55 bsd49 ppp[23743]: Phase: PPP Started (direct mode).
Oct  3 21:51:55 bsd49 ppp[23743]: Phase: bundle: Establish
Oct  3 21:51:55 bsd49 ppp[23743]: Phase: deflink: closed -> opening
Oct  3 21:51:55 bsd49 ppp[23743]: Phase: deflink: Connected!
Oct  3 21:51:55 bsd49 ppp[23743]: Phase: deflink: opening -> carrier
Oct  3 21:51:56 bsd49 ppp[23743]: Phase: deflink: carrier -> lcp
Oct  3 21:51:56 bsd49 ppp[23743]: Phase: bundle: Authenticate
Oct  3 21:51:56 bsd49 ppp[23743]: Phase: deflink: his = CHAP 0x81, mine = none
Oct  3 21:51:56 bsd49 ppp[23743]: Phase: Chap Input: CHALLENGE (16 bytes)
Oct  3 21:51:56 bsd49 ppp[23743]: Phase: Chap Output: RESPONSE (6/0568)
Oct  3 21:51:56 bsd49 ppp[23743]: Phase: Chap Input: SUCCESS (S=12A71949EA48FF339CECA958F4A17D0BC052E054)
Oct  3 21:51:56 bsd49 ppp[23743]: Phase: deflink: lcp -> open
Oct  3 21:51:56 bsd49 ppp[23743]: Phase: bundle: Network
Oct  3 21:51:57 bsd49 ppp[23743]: Warning: iface add: ioctl(SIOCAIFADDR, 192.168.94.7 -> 172.16.1.38): File exists
Oct  3 21:51:57 bsd49 ppp[23743]: Error: ipcp_InterfaceUp: unable to set ip address
Oct  3 21:51:59 bsd49 ppp[23743]: Phase: deflink: open -> lcp
Oct  3 21:51:59 bsd49 ppp[23743]: Phase: bundle: Terminate
Oct  3 21:51:59 bsd49 ppp[23743]: Phase: Signal 15, terminate.
Oct  3 21:52:02 bsd49 ppp[23743]: Phase: deflink: Disconnected!
Oct  3 21:52:02 bsd49 ppp[23743]: Phase: deflink: Connect time: 7 secs: 488 octets in, 506 octets out
Oct  3 21:52:02 bsd49 ppp[23743]: Phase: deflink: 15 packets in, 14 packets out
Oct  3 21:52:02 bsd49 ppp[23743]: Phase:  total 142 bytes/sec, peak 306 bytes/sec on Sun Oct  3 21:51:57 2004
Oct  3 21:52:02 bsd49 ppp[23743]: Phase: deflink: lcp -> closed
Oct  3 21:52:02 bsd49 ppp[23743]: Phase: bundle: Dead
Oct  3 21:52:02 bsd49 ppp[23743]: Phase: PPP Terminated (normal).

почему возникает ошибка добавления ip на интерфейс?