Per packet distribution and tunnel aggregation

This is a sample configuration of aggregating IPsec tunnels by using per-packet load-balancing.

This feature only allows static and DDNS tunnels to be members. Dynamic (dialup) tunnels are not allowed because dialup instances tend to have different locations and hence different routing. This conflicts with the rule that all the members of an aggregate must have the same routing.

For example, a customer has two ISP connections, wan1 and wan2. On each FortiGate, two IPsec VPN interfaces are created. Next, an ipsec-aggregate interface is created and added as an SD-WAN member.

Configuring FortiGate 1

To create two IPsec VPN interfaces:

config vpn ipsec phase1-interface
    edit "vd1-p1"
        set interface "wan1"
        set peertype any
        set net-device disable
        set aggregate-member enable
        set proposal aes256-sha256
        set dhgrp 14
        set remote-gw 172.16.201.2
        set psksecret ftnt1234
    next
    edit "vd1-p2"
        set interface "wan2"
        set peertype any
        set net-device disable
        set aggregate-member enable
        set proposal aes256-sha256
        set dhgrp 14
        set remote-gw 172.16.202.2
        set psksecret ftnt1234
    next
end

config vpn ipsec phase2-interface
    edit "vd1-p1"
        set phase1name "vd1-p1"
    next
    edit "vd1-p2"
        set phase1name "vd1-p2"
    next
end

To create an IPsec aggregate interface:

config system ipsec-aggregate
    edit "agg1"
        set member "vd1-p1" "vd1-p2"
        set algorithm L3
    next
end

config system interface
    edit "agg1"
        set vdom "root"
        set ip 172.16.11.1 255.255.255.255
        set allowaccess ping
        set remote-ip 172.16.11.2 255.255.255.255
end

To configure the firewall policy:

config firewall policy
    edit 1
        set name "1"
        set srcintf "dmz"
        set dstintf ""virtual-wan-link""
        set srcaddr "all"
        set dstaddr "all"
        set action accept
        set schedule "always"
        set service "ALL"
        set nat enable
    next
end

To configure SD-WAN:

config system sdwan
    set status enable
    config members
        edit 1
            set interface "agg1"
            set gateway 172.16.11.2
        next
    end
end

Configuring FortiGate 2

To create two IPsec VPN interfaces:

config vpn ipsec phase1-interface
    edit "vd2-p1"
        set interface "wan1"
        set peertype any
        set net-device disable
        set proposal aes256-sha256
        set dhgrp 14
        set remote-gw 172.16.200.1
        set psksecret ftnt1234
    next
    edit "vd2-p2"
        set interface "wan2"
        set peertype any
        set net-device disable
        set proposal aes256-sha256
        set dhgrp 14
        set remote-gw 172.16.203.1
        set psksecret ftnt1234
    next
end

config vpn ipsec phase2-interface
    edit "vd2-p1"
        set phase1name "vd2-p1"
    next
    edit "vd2-p2"
        set phase1name "vd2-p2"
    next
end

To create an IPsec aggregate interface:

config system ipsec-aggregate
    edit "agg2"
        set member "vd2-p1" "vd2-p2"
        set algorithm L3
    next
end

config system interface
    edit "agg2"
        set vdom "root"
        set ip 172.16.11.2 255.255.255.255
        set allowaccess ping
        set remote-ip 172.16.11.1 255.255.255.255
    next
end

To configure the firewall policy:

config firewall policy
    edit 1
        set name "1"
        set srcintf "dmz"
        set dstintf ""virtual-wan-link""
        set srcaddr "all"
        set dstaddr "all"
        set action accept
        set schedule "always"
        set service "ALL"
        set nat enable
    next
end

To configure SD-WAN on FortiGate 2:

config system sdwan
    set status enable
    config members
        edit 1
            set interface "agg2"
            set gateway 172.16.11.1
        next
    end
end

Related diagnose commands

To display aggregate IPsec members:

# diagnose sys ipsec-aggregate list
agg1 algo=L3 member=2 run_tally=2
members:
        vd1-p1
        vd1-p2

To check the VPN status:

# diagnose vpn tunnel list
list all ipsec tunnel in vd 0
------------------------------------------------------
name=vd1-p1 ver=1 serial=2 172.16.200.1:0->172.16.201.2:0 dst_mtu=0
bound_if=10 lgwy=static/1 tun=intf/0 mode=auto/1 encap=none/520 options[0208]=npu frag-rfc  run_state=1 accept_traffic=0

proxyid_num=1 child_num=0 refcnt=5 ilast=15 olast=676 ad=/0
stat: rxp=0 txp=0 rxb=0 txb=0
dpd: mode=on-demand on=1 idle=20000ms retry=3 count=0 seqno=0
natt: mode=none draft=0 interval=0 remote_port=0
proxyid=vd1-p1 proto=0 sa=0 ref=1 serial=1
  src: 0:0.0.0.0/0.0.0.0:0
  dst: 0:0.0.0.0/0.0.0.0:0
------------------------------------------------------
name=vd1-p2 ver=1 serial=3 172.16.203.1:0->172.16.202.2:0 dst_mtu=1500
bound_if=28 lgwy=static/1 tun=intf/0 mode=auto/1 encap=none/520 options[0208]=npu frag-rfc  run_state=1 accept_traffic=1

proxyid_num=1 child_num=0 refcnt=12 ilast=1 olast=1 ad=/0
stat: rxp=1 txp=1686 rxb=16602 txb=111717
dpd: mode=on-demand on=1 idle=20000ms retry=3 count=0 seqno=0
natt: mode=none draft=0 interval=0 remote_port=0
proxyid=vd1-p2 proto=0 sa=1 ref=9 serial=1
  src: 0:0.0.0.0/0.0.0.0:0
  dst: 0:0.0.0.0/0.0.0.0:0
  SA:  ref=4 options=10226 type=00 soft=0 mtu=1438 expire=42164/0B replaywin=2048
       seqno=697 esn=0 replaywin_lastseq=00000002 itn=0 qat=0
  life: type=01 bytes=0/0 timeout=42902/43200
  dec: spi=f6ae9f83 esp=aes key=16 f6855c72295e3c5c49646530e6b96002
       ah=sha1 key=20 f983430d6c161d0a4cd9007c7ae057f1ff011334
  enc: spi=8c72ba1a esp=aes key=16 6330f8c532a6ca5c5765f6a9a6034427
       ah=sha1 key=20 e5fe385ed5f0f6a33f1d507601b15743a8c70187
  dec:pkts/bytes=1/16536, enc:pkts/bytes=1686/223872
  npu_flag=02 npu_rgwy=172.16.202.2 npu_lgwy=172.16.203.1 npu_selid=2 dec_npuid=1 enc_npuid=0