Ipsec SA src and dst addresses swapped but working

Hello,

I have a RB751U-2HnD at home and a Sonicwall TZ100 at the office. I have a site to site IPSEC tunnel set up and working between them. They each have there own subnet.

The way I got it to work was allowing the Sonicwall to initiate the connection and then having the Routerboard auto generate the policy from the Sonicwall. When I started looking at these auto generated polices I noticed that the SA-SRC-ADDRESS is swapped with the SA-DST-ADDRESS from what I read from the WIKI and it is working fine. Can anyone let me know why this is?

Here are the relevant configuration of the routerboard.

Home and Sonicwall represent the public IPs of each router

HomeNet and SonicwallNet are the local private subnets of each

/ip ipsec peer print
Flags: X - disabled 
 0   address=xxxSonicwallxxx port=500 auth-method=pre-shared-key 
     secret="XXXXXXXXX" generate-policy=yes exchange-mode=main 
     send-initial-contact=no nat-traversal=yes my-id-user-fqdn="" 
     proposal-check=obey hash-algorithm=sha1 enc-algorithm=aes-256 
     dh-group=modp1024 lifetime=1h lifebytes=0 dpd-interval=2m 
     dpd-maximum-failures=5 




/ip ipsec policy print
Flags: X - disabled, D - dynamic, I - inactive
 1 D src-address=SonicwallNet src-port=any dst-address=HomeNet 
     dst-port=any protocol=all action=encrypt level=require 
     ipsec-protocols=esp tunnel=yes sa-src-address=Home 
     sa-dst-address=Sonicwall proposal=default priority=2 

 2 D src-address=SonicwallNet src-port=any dst-address=HomeNet 
     dst-port=any protocol=all action=encrypt level=require 
     ipsec-protocols=esp tunnel=yes sa-src-address=Home
     sa-dst-address=Sonicwall proposal=default priority=2 

 2 D src-address=HomeNet src-port=any dst-address=SonicwallNet 
     dst-port=any protocol=all action=encrypt level=require 
     ipsec-protocols=esp tunnel=yes sa-src-address=Sonicwall 
     sa-dst-address=Home proposal=default priority=2 

/ip ipsec proposal print
Flags: X - disabled 
 0   name="default" auth-algorithms=sha1 enc-algorithms=aes-256 lifetime=8h 
     pfs-group=modp1024 


/ip firewall nat print
Flags: X - disabled, I - invalid, D - dynamic 
 0   chain=srcnat action=accept src-address=HomeNet
     dst-address=SonicwallNet 

 1   ;;; default configuration
     chain=srcnat action=masquerade out-interface=ether1-gateway