Wireguard Speed Issue

[yodaphone]

after i upgraded to 22.1.3, i'm having a weird wireguard S2S issue

1. Both use 22.1.3 with WG kmod
2. When i do an iperf test, SITE A to SITE B gives me an avg. of 14 Mbps (which is normal)
3. When i do an iperf test, SITE B to SITE A gives me an avg. of 322 Kbits/sec - 

The pings from either side are pretty much the same.

From SITE A TO SITE B

iperf3 -c 192.168.3.1 (SITE B)
Connecting to host 192.168.3.1, port 5201
[  5] local 10.17.0.1 port 20525 connected to 192.168.3.1 port 5201
[ ID] Interval           Transfer     Bitrate         Retr  Cwnd
[  5]   0.00-1.00   sec   213 KBytes  1.74 Mbits/sec    0   96.2 KBytes
[  5]   1.00-2.00   sec  1.25 MBytes  10.5 Mbits/sec    0    490 KBytes
[  5]   2.00-3.01   sec  3.31 MBytes  27.6 Mbits/sec  113    208 KBytes
[  5]   3.01-4.00   sec  3.22 MBytes  27.1 Mbits/sec  236    442 KBytes
[  5]   4.00-5.00   sec  1.64 MBytes  13.8 Mbits/sec    0    448 KBytes
[  5]   5.00-6.00   sec  1.56 MBytes  13.1 Mbits/sec    0    452 KBytes
[  5]   6.00-7.00   sec  1.62 MBytes  13.6 Mbits/sec    0    457 KBytes
[  5]   7.00-8.00   sec  1.07 MBytes  9.00 Mbits/sec    1    232 KBytes
[  5]   8.00-9.00   sec   832 KBytes  6.82 Mbits/sec    0    238 KBytes
[  5]   9.00-10.00  sec   870 KBytes  7.12 Mbits/sec    0    242 KBytes
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bitrate         Retr
[  5]   0.00-10.00  sec  15.5 MBytes  13.0 Mbits/sec  350             sender
[  5]   0.00-10.27  sec  13.8 MBytes  11.2 Mbits/sec                  receiver

PING STATS


ping 192.168.3.1
PING 192.168.3.1 (192.168.3.1): 56 data bytes
64 bytes from 192.168.3.1: icmp_seq=0 ttl=64 time=268.734 ms
64 bytes from 192.168.3.1: icmp_seq=1 ttl=64 time=268.170 ms
64 bytes from 192.168.3.1: icmp_seq=2 ttl=64 time=267.838 ms
64 bytes from 192.168.3.1: icmp_seq=3 ttl=64 time=268.463 ms
64 bytes from 192.168.3.1: icmp_seq=4 ttl=64 time=268.048 ms
64 bytes from 192.168.3.1: icmp_seq=5 ttl=64 time=267.684 ms
64 bytes from 192.168.3.1: icmp_seq=6 ttl=64 time=267.763 ms
^C
--- 192.168.3.1 ping statistics ---
7 packets transmitted, 7 packets received, 0.0% packet loss
round-trip min/avg/max/stddev = 267.684/268.100/268.734/0.358 ms



From SITE B TO SITE A

iperf3 -c 192.168.11.1 -p 5201
Connecting to host 192.168.11.1, port 5201
[  5] local 10.17.0.2 port 34521 connected to 192.168.11.1 port 5201
[ ID] Interval           Transfer     Bitrate         Retr  Cwnd
[  5]   0.00-1.01   sec   118 KBytes   955 Kbits/sec    1   22.7 KBytes
[  5]   1.01-2.00   sec   114 KBytes   940 Kbits/sec    1   14.7 KBytes
[  5]   2.00-3.00   sec  40.1 KBytes   329 Kbits/sec    2   9.38 KBytes
[  5]   3.00-4.00   sec  14.7 KBytes   120 Kbits/sec    2   5.37 KBytes
[  5]   4.00-5.00   sec  26.7 KBytes   218 Kbits/sec    0   10.8 KBytes
[  5]   5.00-6.00   sec  30.7 KBytes   252 Kbits/sec    1   9.40 KBytes
[  5]   6.00-7.00   sec  32.1 KBytes   263 Kbits/sec    0   13.4 KBytes
[  5]   7.00-8.01   sec  37.4 KBytes   304 Kbits/sec    1   10.7 KBytes
[  5]   8.01-9.00   sec  44.1 KBytes   363 Kbits/sec    1   8.04 KBytes
[  5]   9.00-10.01  sec  21.4 KBytes   173 Kbits/sec    1   5.37 KBytes
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bitrate         Retr
[  5]   0.00-10.01  sec   479 KBytes   392 Kbits/sec   10             sender
[  5]   0.00-10.29  sec   405 KBytes   322 Kbits/sec                  receiver

PING STATS

 ping 192.168.11.1
PING 192.168.11.1 (192.168.11.1): 56 data bytes
64 bytes from 192.168.11.1: icmp_seq=0 ttl=64 time=267.604 ms
64 bytes from 192.168.11.1: icmp_seq=1 ttl=64 time=268.597 ms
64 bytes from 192.168.11.1: icmp_seq=2 ttl=64 time=268.139 ms
64 bytes from 192.168.11.1: icmp_seq=3 ttl=64 time=269.240 ms
64 bytes from 192.168.11.1: icmp_seq=4 ttl=64 time=268.669 ms
64 bytes from 192.168.11.1: icmp_seq=5 ttl=64 time=270.352 ms
64 bytes from 192.168.11.1: icmp_seq=6 ttl=64 time=270.733 ms
64 bytes from 192.168.11.1: icmp_seq=7 ttl=64 time=269.979 ms
64 bytes from 192.168.11.1: icmp_seq=8 ttl=64 time=267.509 ms
^C
--- 192.168.11.1 ping statistics ---
9 packets transmitted, 9 packets received, 0.0% packet loss
round-trip min/avg/max/stddev = 267.509/268.980/270.733/1.107 ms


There was no change in config from the previous version. I tried setting the MTU to 1420 but still no luck

Any help will be greatly appreciated.

PS: Tried it with a wireguard client from SITE A TO SITE B, same issue

[jezza007]

I recall I had similar symptom when I first setup

I recall reading about MTU for Wireguard peer, just checked my config and recall I found 1384 was optimal which resolved issues I was having

https://www.reddit.com/r/WireGuard/comments/plm8y7/finding_the_optimal_mtu_for_wg_server_and_wg_peer/

https://gist.github.com/nitred/f16850ca48c48c79bf422e90ee5b9d95

[tiermutter]

I found MTU 1395 is working fine for me on Windows machines. With default 1500 I remember I had similiar issues since 22.1 (fresh install). I'm using WG-go.