[strongSwan] High latencies

[Noel Kuntze]

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Did you fix the MSS? Is the MTU on the tunnel correct? Did you maybe break PMTU discovery?


On 19.09.2017 15:53, Turbo Fredriksson wrote:
> I’m not sure if this is a Strongswan problem, but I see some indications > that it might be, so I’m posting it here. If this is not the right place, let me > know and I’ll take it elsewhere. > > > I have setup a new region (London) in our AWS environment and are > trying to connect one of instances in there to our ElastiCache (Redis3.2) > cluster which is located in London. > > > I get latencies of 20ms (not sure if that’s to much of it’s just a fluke). > > EC2 Instance (Redis client London) -> EC2 Instance (London VPN) -> VPN -> EC2 Instance (Ireland VPN) -> Redis > > From any instance in Ireland, I get a latency of less than 1ms… > > EC2 Instance (Redis client Ireland) -> Redis > > If I try it from my laptop at work, it’s about 15ms. > > Laptop (Redis client Office) -> VPN -> EC2 Instance (Ireland VPN) -> Redis > > > > If I strace the redis-cli command on ‘Redis client London’, I see that the > initial connect completes without any (noticeable) delay. However, GET > on a value (~14kb), never completes. If I do it from a telnet session directly
> to the Redis cluster, the GET eventually completes (one or two minutes). > -----BEGIN PGP SIGNATURE-----

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