Hello,
we have a problem with CCR1016-12G. We have activated a L2TP server on it. We can connect Mikrotik by L2TP client VPN from home or using mobile internet, it seems to work. But from different company we can not. The client PC with L2TP vpn client in this case is behind Checkpoint Firewall.
We collected pcap file on Mikrotik and we can see this kind of picture:
Source is client, destination is Mikrotik
source 56053 > destination 500
destination 500 > source 56053
source 56053 > destination 500
destination 500 > source 56053
source 44907 > destination 4500
source 44907 > destination 4500
source 44907 > destination 4500
source 44907 > destination 4500
source 44907 > destination 4500
source 4500 > destination 44907
And everything is starting from beginning.
While on the same Mikrotik router from different IP address we have a response from Mikrotik:
source 19855 > destination 500
destination 500 > source 19855
source 19855 > destination 500
destination 500 > source 19855
source 58093 > destination 4500
destination 4500 > source 58093
And establishing connection.
What can be a problem?