Hi, Looks like your firewall rules on the hub are broken and cause the problems or you need to configure an additional CHILD_SA to tunnel ICMP errors from the hub, because it has no IP in the local TS. Check both those suspicions.
Kind regards Noel On 27.12.2017 23:00, Martin Sand wrote: > Thanks again Noel. > > I have executed `traceroute -T --mtu <destination>` and `mtr -rw > <destination>` on machines at both locations. > I did not do further investigation on the MSS yet since I have this strange > packet loss. > Based on the route, I assume this happens at the hub which is in between the > two routers? > Could this be the root cause I need to further investigate? > > Kind regards > Martin > > traceroute -T --mtu pi-frankfurt > traceroute to pi-frankfurt (192.168.2.135), 30 hops max, 60 byte packets > 1 router-freiburg (192.168.1.1) 0.263 ms 0.179 ms 0.172 ms > 2 * * * > 3 router-frankfurt (192.168.2.1) 41.762 ms 41.182 ms 36.716 ms > 4 pi-frankfurt (192.168.2.135) 36.693 ms 43.629 ms 37.051 ms > > traceroute -T --mtu pi-freiburg > traceroute to pi-freiburg (192.168.1.130), 30 hops max, 60 byte packets > 1 router-frankfurt (192.168.2.1) 0.489 ms 0.381 ms 0.287 ms > 2 * * * > 3 router-freiburg (192.168.1.1) 38.368 ms 47.673 ms 35.441 ms > 4 pi-freiburg (192.168.1.130) 39.456 ms 54.566 ms 36.117 ms > > mtr -rw pi-frankfurt > Start: 2017-12-27T22:57:40+0100 > HOST: workstation Loss% Snt Last Avg Best Wrst StDev > 1.|-- router-freiburg 0.0% 10 0.2 0.2 0.2 0.3 0.0 > 2.|-- ??? 100.0 10 0.0 0.0 0.0 0.0 0.0 > 3.|-- router-frankfurt 0.0% 10 33.3 35.5 32.5 42.0 2.7 > 4.|-- pi-frankfurt 0.0% 10 33.5 34.4 32.7 36.7 1.5 > > > On 27.12.2017 21:08, Noel Kuntze wrote: >> Hi, >> >> You can test the convergence speed using `traceroute -T --mtu >> <destination>`, but that only gives you the MTU. You need to manually >> discover the MSS >> using `traceroute -T -O mss=<mss> <destination>`. >> >> The best way to check if the problem continues is to just run >> tcpdump/wireshark and check for ICMP Fragmenation needed packets and TCP >> errors or timeouts. >> >> Kind regards >> >> Noel >> >> On 27.12.2017 17:12, Martin Sand wrote: >>> Thanks Noel. Sorry, I had to travel to the other location (350 km). >>> >>> I adapted the iptable rules. It improved, but I have the impression it only >>> improved a bit. >>> Is there a way to measure MTU discovery time? >>> >>> Kind regards >>> Martin >>> >>> >>> On 14.12.2017 13:51, Noel Kuntze wrote: >>>> Hi, >>>> >>>>> VPN internal http requests to a web server of another spoke take some >>>>> time until the page is rendered. >>>>> I assume this is due to the latency. >>>> Nah. It's extremely more likely that the path MTU discovery takes some >>>> time (maybe due to some missing/wrong firewall rules on some host(s) in >>>> your network topology). >>>> Try lowering the MTU and MSS of the tunneled traffic[1]. >>>> >>>> Kind regards >>>> >>>> Noel >>>> >>>> [1] >>>> https://wiki.strongswan.org/projects/strongswan/wiki/ForwardingAndSplitTunneling#MTUMSS-issues >>>> >>>> On 14.12.2017 13:41, Martin Sand wrote: >>>>> Hi all >>>>> >>>>> I have a Hub and Spoke setup. Connections are working perfectly fine. >>>>> Throughput is almost reaching the maximum rate of the upload channel >>>>> speed, 10 MBit/s. >>>>> >>>>> Unfortunately the latency is not fulfilling my objectives. I have an >>>>> average ping time of 39 ms (see below) when pinging clients on other >>>>> spokes. >>>>> VPN internal http requests to a web server of another spoke take some >>>>> time until the page is rendered. >>>>> I assume this is due to the latency. >>>>> >>>>> Is there any chance to improve the latency? Or is the latency perfectly >>>>> good? >>>>> >>>>> Best regards >>>>> Martin >>>>> >>>>> Hub internet address >>>>> 64 bytes from vpn.example.com (217.122.5.6): icmp_seq=1 ttl=57 time=15.2 >>>>> ms >>>>> >>>>> Internal address of Hub >>>>> PING 192.168.1.1 (192.168.1.1) 56(84) bytes of data. >>>>> 64 bytes from 192.168.1.1: icmp_seq=1 ttl=62 time=40.4 ms >>>>> >>>>> Client on another spoke >>>>> PING 192.168.1.130 (192.168.1.130) 56(84) bytes of data. >>>>> 64 bytes from 192.168.1.130: icmp_seq=1 ttl=61 time=108 ms >>>>> 64 bytes from 192.168.1.130: icmp_seq=2 ttl=61 time=41.8 ms >>>>> 64 bytes from 192.168.1.130: icmp_seq=3 ttl=61 time=38.0 ms >>>>> 64 bytes from 192.168.1.130: icmp_seq=4 ttl=61 time=35.2 ms >>>>> 64 bytes from 192.168.1.130: icmp_seq=5 ttl=61 time=36.4 ms >>>>> 64 bytes from 192.168.1.130: icmp_seq=6 ttl=61 time=39.1 ms >>>>> 64 bytes from 192.168.1.130: icmp_seq=7 ttl=61 time=38.1 ms >>>>> 64 bytes from 192.168.1.130: icmp_seq=8 ttl=61 time=41.6 ms >>>>> 64 bytes from 192.168.1.130: icmp_seq=9 ttl=61 time=36.0 ms >>>>> 64 bytes from 192.168.1.130: icmp_seq=10 ttl=61 time=36.7 ms >>>>> >>>>> --- 192.168.1.130 ping statistics --- >>>>> 10 packets transmitted, 10 received, 0% packet loss, time 9013ms >>>>> rtt min/avg/max/mdev = 35.295/45.159/108.281/21.146 ms >>>>> >
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