Good day I have some issues here I have built an L2l VPN from my location to AWS London, I can see that the tunnel is up but when I attempt to connect our local domain controller here in our office to AWS London I can see TCP timing out but UDP works. On my ACL I do not have any port restrictions so I am at a lost on why UDP works but not TCP. What I find strange is when TCP trys to connect I see in the logs the following: Jun 05 2019 03:54:10: %ASA-6-302013: Built inbound TCP connection 408579111 for INSIDE:10.16.10.15/65059 (10.190.0.15/65059) to INSIDE:10.20.0.115/88 (10.20.0.115/88) Jun 05 2019 03:54:10: %ASA-6-302013: Built inbound TCP connection 408579112 for INSIDE:10.190.0.15/65059 (10.190.0.15/65059) to INSIDE:10.20.0.115/88 (10.20.0.115/88) Jun 05 2019 03:54:10: %ASA-4-419002: Duplicate TCP SYN from INSIDE:10.190.0.15/65059 to INSIDE:10.20.0.115/88 with different initial sequence number Jun 05 2019 03:54:10: %ASA-4-419002: Duplicate TCP SYN from INSIDE:10.190.0.15/65059 to INSIDE:10.20.0.115/88 with different initial sequence number Jun 05 2019 03:54:10: %ASA-4-419002: Duplicate TCP SYN from INSIDE:10.190.0.15/65059 to INSIDE:10.20.0.115/88 with different initial sequence number I see a whole lot of this duplicate tcp SYN messages then it eventually times out. My configs are as follows: object network dw01 host 10.16.10.103 object network dw01-NATLDN host 10.190.0.103 object network dc03 host 10.16.10.15 object network dc03-NATLDN host 10.190.0.15 object-group network Amazon.LocalLDN network-object 10.190.0.0 255.255.255.0 object-group network Amazon-RemoteLDN network-object 10.20.0.0 255.255.0.0 access-list OUTSIDE_cryptomap_10 extended permit ip any object-group Amazon-RemoteLDN access-list amznLDN-filter extended permit ip 10.20.0.0 255.255.0.0 10.190.0.0 255.255.255.0 nat (INSIDE,OUTSIDE) source static dw01 dw01-NATLDN destination static Amazon-RemoteLDN Amazon-RemoteLDN nat (INSIDE,any) source static network dc03 dc03-NATLDN destination static Amazon-RemoteLDN Amazon-RemoteLDN crypto ipsec ikev1 transform-set transform-amzn esp-aes esp-sha-hmac crypto map OUTSIDE_map 15 match address OUTSIDE_cryptomap_10 crypto map OUTSIDE_map 15 set pfs group2 crypto map OUTSIDE_map 15 set peer 52.56.71.96 3.8.226.22 crypto map OUTSIDE_map 15 set ikev1 transform-set transform-amzn crypto map OUTSIDE_map 15 set security-association lifetime seconds 3600 crypto map OUTSIDE_map 15 set nat-t-disable tunnel-group 52.56.71.96 type ipsec-l2l tunnel-group 52.56.71.96 general-attributes default-group-policy Amazon-LDN tunnel-group 52.56.71.96 ipsec-attributes ikev1 pre-shared-key isakmp keepalive threshold 10 retry 10 group-policy Amazon-LDN internal group-policy Amazon-LDN attributes vpn-idle-timeout none vpn-session-timeout none vpn-filter value amznLDN-filter vpn-tunnel-protocol ikev1 Thank you in advance for your help!!