IPSec VPN tunnels unstable in RouterOS 3.31?

Hi all,

I have five locations each connected with a Mikrotik 750G router. Works great … except the static VPN IPSec tunnels between locations.

The tunnels work … the example page in the manual was a great help. However, the tunnels go down randomly and I must log in, do a “ping src-address=” a few times on each box to bring up the tunnels again.

There seems to be no rhyme nor reason to when the tunnels go down, and why several pings are needed to bring up the tunnel. Many times I just get “Packet rejected” and the tunnel doesn’t get built.

An example policy:

/ip ipsec policy print
 0  src-a0ddress=192.168.10.0/24:any dst-address=192.168.0.0/24:any 
     protocol=all action=encrypt level=require ipsec-protocols=esp tunnel=yes 
     sa-src-address=[real ip of local router wan] sa-dst-address=[real ip of remote router wan]
     proposal=default priority=0

A peer definition:

/ip ipsec peer print
 0   address=[remote real ip]/32:500 auth-method=pre-shared-key secret="********>
     generate-policy=no exchange-mode=aggressive send-initial-contact=yes 
     nat-traversal=no proposal-check=obey hash-algorithm=md5 
     enc-algorithm=3des dh-group=modp1024 lifetime=1d lifebytes=0 
     dpd-interval=disable-dpd dpd-maximum-failures=1

Proposal:

/ip ipsec proposal> print
 0   name="default" auth-algorithms=md5 enc-algorithms=3des lifetime=1h 
     pfs-group=modp1024

I also have the proper rules in /ip firewall nat to exclude VPN packets from being NAT’d.

Is this a bug or am I doing something wrong? Thanks in advance for any help!

-Andrew in Honduras

  1. Check that you have the same lifetime on each router.
  2. Try to netwach hosts and flush-sa when host is down.

I setup a 3.30 MT with a IPSec tunnel to a sonicwall on the other end of the tunnel for someone back in December, haven’t had a single problem with it.

verify your lifetime settings are set exactly the same on both sides, they need to match on both the phase 1 and the phase 2 part of the connection.