Slow TCP in one direction only on VPN
by NetAcademic9904
I have two sites, A and B - connected by a S2S IPSec VPN on gigabit links. Site A has a Fortigate 400E running latest v7.2. Site B has a Fortigate 120G running latest v7.6. Site B is able to line-rate on iPerf3 to A on TCP/UDP. Site A is able to line-rate on iPerf3 to B on UDP only. TCP is very slow (less than 1% of UDP). I have the same config on both sides. VPN interface(s) have tcp-mss set to 1418 on both sides. No profiles applied to impact performance. DH is 21 w/ AES256GCM-PRFSHA384 if it makes any difference. What am I missing here? Thanks, real head scratcher. submitted by /u/NetAcademic9904 [link] [comments]