Wireguard is loosing connection for no reason

[Pavel Yegorov <yegorov.p@gmail.com>]

Hey folks!

I really need some advice, cause I just don't know how to deal with my problem.

So, I have a WG "server" on ubuntu 18.04.6 LTS, hosted in the oracle
free tier. I've installed wireguard using well-known
https://github.com/angristan/wireguard-install script. Then I've
generated several configs for my desktops, phones, etc. It connects
and runs perfectly, but sometimes it just freezes for no reason.
There's no connectivity issues or something like that. Logs on client
side says something like that:

2022-06-21 03:01:01.845: [TUN] [win] Keypair 17 created for peer 1
2022-06-21 03:01:01.846: [TUN] [win] Sending keepalive packet to peer
1 (SERVER_IP:SERVER_PORT)
2022-06-21 03:03:01.822: [TUN] [win] Sending handshake initiation to
peer 1 (SERVER_IP:SERVER_PORT)
2022-06-21 03:03:01.884: [TUN] [win] Receiving handshake response from
peer 1 (SERVER_IP:SERVER_PORT)
2022-06-21 03:03:01.884: [TUN] [win] Keypair 16 destroyed for peer 1
2022-06-21 03:03:01.884: [TUN] [win] Keypair 18 created for peer 1
2022-06-21 03:03:01.884: [TUN] [win] Sending keepalive packet to peer
1 (SERVER_IP:SERVER_PORT)
2022-06-21 03:05:02.058: [TUN] [win] Sending handshake initiation to
peer 1 (SERVER_IP:SERVER_PORT)
2022-06-21 03:05:02.106: [TUN] [win] Receiving handshake response from
peer 1 (SERVER_IP:SERVER_PORT)
2022-06-21 03:05:02.106: [TUN] [win] Keypair 17 destroyed for peer 1
2022-06-21 03:05:02.106: [TUN] [win] Keypair 19 created for peer 1
2022-06-21 03:05:02.106: [TUN] [win] Sending keepalive packet to peer
1 (SERVER_IP:SERVER_PORT)
2022-06-21 03:06:21.302: [TUN] [win] Retrying handshake with peer 1
(SERVER_IP:SERVER_PORT) because we stopped hearing back after 15
seconds
2022-06-21 03:06:21.302: [TUN] [win] Sending handshake initiation to
peer 1 (SERVER_IP:SERVER_PORT)
2022-06-21 03:06:26.423: [TUN] [win] Handshake for peer 1
(SERVER_IP:SERVER_PORT) did not complete after 5 seconds, retrying
(try 2)
2022-06-21 03:06:26.423: [TUN] [win] Sending handshake initiation to
peer 1 (SERVER_IP:SERVER_PORT)
2022-06-21 03:06:31.471: [TUN] [win] Handshake for peer 1
(SERVER_IP:SERVER_PORT) did not complete after 5 seconds, retrying
(try 3)
2022-06-21 03:06:31.473: [TUN] [win] Sending handshake initiation to
peer 1 (SERVER_IP:SERVER_PORT)
2022-06-21 03:06:36.517: [TUN] [win] Handshake for peer 1
(SERVER_IP:SERVER_PORT) did not complete after 5 seconds, retrying
(try 4)

If I reconnect WG client, it immediately connects and everything is ok.

Any advices? I tried to experiment with PersistentKeepAlive param (on
both sides!) that doesn't change anything.

My server cfg:

[Interface]
Address = 10.66.66.1/24,fd42:42:42::1/64
ListenPort = SERVER_PORT
PrivateKey = M?????Uyg4r3mo=

PostUp = iptables -I FORWARD -i ens3 -o wg0 -j ACCEPT; iptables -I
FORWARD -i wg0 -j ACCEPT; iptables -t nat -A POSTROUTING -o ens3 -j
MASQUERADE; ip6tables -A FORWARD -i wg0 -j ACCEPT; ip6tables -t nat -A
POSTROUTING -o ens3 -j MASQUERADE; sudo iptables -I INPUT -i ens3 -p
udp --dport SERVER_PORT -m state --state NEW,ESTABLISHED -j ACCEPT
PostDown = iptables -D FORWARD -i ens3 -o wg0 -j ACCEPT; iptables -D
FORWARD -i wg0 -j ACCEPT; iptables -t nat -D POSTROUTING -o ens3 -j
MASQUERADE; ip6tables -D FORWARD -i wg0 -j ACCEPT; ip6tables -t nat -D
POSTROUTING -o ens3 -j MASQUERADE; sudo iptables -D INPUT -i ens3 -p
udp --dport SERVER_PORT -m state --state NEW,ESTABLISHED -j ACCEPT

### Client iphone
[Peer]
PublicKey = 0+V???????4HnM=
PresharedKey = s???????amJCxJyqcE=
AllowedIPs = 10.66.66.2/32,fd42:42:42::2/128

### Client mac
[Peer]
PublicKey = Tet4??????mI=
PresharedKey = Ld???r8=
AllowedIPs = 10.66.66.3/32,fd42:42:42::3/128

My client cfg

[Interface]
PrivateKey = 4Bp????=
Address = 10.66.66.2/32,fd42:42:42::2/128
DNS = 8.8.8.8,1.1.1.1

[Peer]
PublicKey = 5R?????c=
PresharedKey = sY????E=
Endpoint = SERVER_IP:SERVER_PORT
AllowedIPs = 0.0.0.0/0,::/0

some stats

root@oraclevpn:~# wg show all
interface: wg0
  public key: 5R?????c=
  private key: (hidden)
  listening port: SERVER_PORT

peer: 0+?????nM=
  preshared key: (hidden)
  endpoint: 666.666.666.666:11111
  allowed ips: 10.66.66.2/32, fd42:42:42::2/128
  latest handshake: 2 minutes, 2 seconds ago
  transfer: 533.52 MiB received, 5.18 GiB sent


-- 
Pavel Yegorov