Date: Mon, 5 Oct 1998 10:53:24 -0700 From: Jeff Kletsky <Jeff@Wagsky.com> To: questions@FreeBSD.ORG Subject: ppp -auto -alias and 1st connection w/ dynamic IP Message-ID: <l03110700b23eb36a384f@[192.168.6.3]>
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With an ISP that provides dynamically-assigned IP numbers, I am observing that ppp -auto -alias sf will dial properly when a command such as telnet some.outside.host is issued, but the connection is not established. Once the link is up, everything seems to function "correctly." (telnet "immediately" connects) My guess is that the packets which caused the dial to occur are (incorrectly) aliased to the "last" IP number assigned to the interface. When the link comes up, the interface's new address is different -- the return packets are not recognized as destined for the PPP-client machine (not to mention that the ISP's routers are sending the packet to another machine!). Virtually the same configuration works quite well with a static IP address. Is there a way to change this behavior so that an initial connection is properly established when using demand dialing, aliasing, and dynamically assigned IP? Thanks! Jeff Notes: in ppp.conf, ! /sbin/ipfw add 100 allow all from MYADDR to any out via tun0 is to allow packets for the inital "dummy" tun0 address to pass and initiate dialing. Subsequent dial attempts are from the "last" IP address, and the firewall is still passing them (it is not reset or closed when the link goes down). in ppp.linkup, ! /etc/firewall/firewall.ppp MYADDR resets the firewall rules to reflect the "new" value (MYADDR) for the tun0 interface IP address. %%%%% ppp.conf: ################################################################# # # PPP Sample Configuration File # # Written by Toshiharu OHNO # # $Id: ppp.conf,v 1.3.1.1 1997/11/15 23:54:27 root Exp root $ # ################################################################# # Default setup. Always executed when PPP is invoked. # # Modem initialization: # # &F1 Hardware flow control template # M0 Speaker off # &U14 Minimum carrier of 28,800 # &N0 No maximum carrier # S7 Wait time for carrier default: set log Carrier Connect Link Phase IPCP set server /var/run/tun0.ctl 0177 set device /dev/cuaa1 set speed 115200 set dial "TIMEOUT 3 ABORT BUSY ABORT \"NO CARRIER\" ABORT \"NO DIAL\" \"\" AT OK-+++-OK ATH0 OK AT\&F0M1W2S7=40 OK \"ATDT \\\\T\" TIMEOUT 70 CONNECT \"\"" set redial 1.1 5 enable throughput deny lqr set timeout 300 load filters load ntpdrop show route # # Dialup and keep-alive filters # nodial: set dfilter -1 set dfilter 19 deny # # No ICMP for dialup or keep-alive # filters: set dfilter -1 set dfilter 0 deny icmp set dfilter 19 permit 0/0 0/0 set afilter -1 set afilter 0 deny icmp set afilter 19 permit 0/0 0/0 # # No NTP passes when link is down # ntpdrop: set ofilter 0 deny udp src eq 123 set ofilter 1 deny udp dst eq 123 set ofilter 19 permit 0/0 0/0 # # but NTP permitted when link is up # ntppass: set ofilter 0 permit udp src eq 123 set ofilter 1 permit udp dst eq 123 set ofilter 19 permit 0/0 0/0 alias_options: alias same_ports yes alias use_sockets yes alias unregistered_only yes # Common stuff for all Best Communications pops best: set authname "*****" set authkey "*****" set login "TIMEOUT 10 ogin:--ogin: \\U assword: \\P" set ifaddr 192.168.0.1/0 10.0.0.1/0 255.255.255.0 0.0.0.0 ! /sbin/ipfw add 100 allow all from MYADDR to any out via tun0 delete default delete ALL add 0 0 HISADDR load alias_options sf: load best set phone 555-5555 show modem show route %%%%% ppp.linkup: MYADDR: set ofilter 0 permit udp src eq 123 set ofilter 1 permit udp dst eq 123 set ofilter 19 permit 0/0 0/0 delete ALL add 0 0 HISADDR ! echo MYADDR ! /etc/firewall/firewall.ppp MYADDR %%%%% ppp.linkdown: MYADDR: set ofilter 0 deny udp src eq 123 set ofilter 1 deny udp dst eq 123 set ofilter 19 permit 0/0 0/0 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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