WAN回線はISP-A(ppp0 over eth1)をメイン回線とします。
このメイン回線に障害が発生しppp0インターフェースがダウンした場合、インターフェーストリガー機能でバックアップ用のISP-B(ppp1 over port1.0.4)の回線に切り替えるスクリプトを実行します。
メイン回線が復旧しppp0インターフェースがアップしたら、バックアップ回線(ppp1)を切断し元のメイン回線に戻します。
zone public
network ISP-A
ip subnet 0.0.0.0/0 interface ppp0
host ppp0
ip address dynamic interface ppp0
network ISP-B
ip subnet 0.0.0.0/0 interface ppp1
host ppp1
ip address dynamic interface ppp1
firewall
rule 10 permit dhcp from private.dhcp to private.dhcp
rule 20 permit any from private.lan to private.lan
rule 30 permit any from private.lan to public
rule 40 permit dns from public.ISP-A.ppp0 to public.ISP-A
rule 50 permit dns from public.ISP-B.ppp1 to public.ISP-B
protect
!
no spanning-tree rstp enable
!
interface eth1
encapsulation ppp 0
!
interface ppp0
ppp ipcp dns request
keepalive
ip address negotiated
ppp username user@ispA
ppp password isppasswdA
ip tcp adjust-mss pmtu
!
interface port1.0.4
no switchport
encapsulation ppp 1
!
interface ppp1
ppp ipcp dns request
keepalive
ip address negotiated
ppp username user@ispB
ppp password isppasswdB
ip tcp adjust-mss pmtu
shutdown
!
interface vlan1
ip address 192.168.10.1/24
!
zone private
network dhcp
ip subnet 0.0.0.0/0 interface vlan1
network lan
ip subnet 192.168.10.0/24
!
zone public
network ISP-A
ip subnet 0.0.0.0/0 interface ppp0
host ppp0
ip address dynamic interface ppp0
network ISP-B
ip subnet 0.0.0.0/0 interface ppp1
host ppp1
ip address dynamic interface ppp1
!
application dhcp
protocol udp
dport 67 to 68
!
firewall
rule 10 permit dhcp from private.dhcp to private.dhcp
rule 20 permit any from private.lan to private.lan
rule 30 permit any from private.lan to public
rule 40 permit dns from public.ISP-A.ppp0 to public.ISP-A
rule 50 permit dns from public.ISP-B.ppp1 to public.ISP-B
protect
!
nat
rule 10 masq any from private to public
enable
!
ip dhcp pool pool10
network 192.168.10.0 255.255.255.0
range 192.168.10.100 192.168.10.131
default-router 192.168.10.1
dns-server 192.168.10.1
lease 0 2 0
!
service dhcp-server
!
trigger 1
type interface ppp0 down
script 1 flash:/ppp0down.scp
trigger 2
type interface ppp0 up
script 1 flash:/ppp0up.scp
!
ip dns forwarding
!
ip route 0.0.0.0/0 ppp0
ip route 0.0.0.0/0 ppp1 10
!
end