KumoProxy Issues

KumoMTA Troubleshooting
1

It looks like I am having some weird, connection issues with KumoMTA right now. Some emails are going through, some are not.

failed to connect to PROXY_ADDRESS:5000 Socks5 { server: PROXY_ADDRESS:5000, source: MTA_IP, destination: 142.250.27.26:25 }: Connection refused (os error 111)
3 
failed to connect to XXXXXX:5000 Socks5 { server: XXXXXXX:5000, source: XXXXXX, destination: 108.177.125.27:25, username_and_password: None }: Connection refused (os error 111)
4

I had to restart Kumo proxy and now it works

5

The service was running fine though:

root@kproxy1:~# systemctl status kumoproxy.service
● kumoproxy.service - KumoMTA SOCKS5 Proxy service
     Loaded: loaded (/etc/systemd/system/kumoproxy.service; enabled; preset: enabled)
     Active: active (running) since Thu 2025-09-11 04:44:01 UTC; 6 days ago
   Main PID: 844 (proxy-server)
      Tasks: 3 (limit: 2260)
     Memory: 3.3M (peak: 43.2M)
        CPU: 16min 48.845s
     CGroup: /system.slice/kumoproxy.service
             └─844 /opt/kumomta/sbin/proxy-server --listen 0.0.0.0:5000

Sep 18 02:54:27 kproxy1 proxy-server[844]: [2025-09-18T02:54:27Z ERROR proxy_server] proxy session >
Sep 18 02:54:27 kproxy1 proxy-server[844]: [2025-09-18T02:54:27Z ERROR proxy_server] proxy session >
Sep 18 02:54:31 kproxy1 proxy-server[844]: [2025-09-18T02:54:31Z ERROR proxy_server] proxy session >
Sep 18 02:54:32 kproxy1 proxy-server[844]: [2025-09-18T02:54:32Z ERROR proxy_server] proxy session >
Sep 18 02:54:34 kproxy1 proxy-server[844]: [2025-09-18T02:54:34Z ERROR proxy_server] proxy session >
Sep 18 02:54:42 kproxy1 proxy-server[844]: [2025-09-18T02:54:42Z ERROR proxy_server::proxy_handler]>
Sep 18 02:54:43 kproxy1 proxy-server[844]: [2025-09-18T02:54:43Z ERROR proxy_server::proxy_handler]>
Sep 18 02:54:49 kproxy1 proxy-server[844]: [2025-09-18T02:54:49Z ERROR proxy_server] proxy session >
Sep 18 02:55:23 kproxy1 proxy-server[844]: [2025-09-18T02:55:23Z ERROR proxy_server] proxy session >
Sep 18 03:03:31 kproxy1 proxy-server[844]: [2025-09-18T03:03:31Z ERROR proxy_server] proxy session >
6 
Sep 18 02:54:27 kproxy1 proxy-server[844]: [2025-09-18T02:54:27Z ERROR proxy_server] proxy session error: Too many open files (os error 24)
Sep 18 02:54:27 kproxy1 proxy-server[844]: [2025-09-18T02:54:27Z ERROR proxy_server] accept failed: Too many open files (os error 24)
7

Okay, this is good

8

Let me check the sysctl config

9

My first production accident was because of this too many open files :laughing:

10

Lmaoo

11

What is ur current level?

12

500,000 :laughing:

13

However, according to the current monitor, the highest is 220,000

14

image.png
image.png1932×694 98.4 KB

15

Why did it kinda freeze tho :slightly_frowning_face:

16

It should have accepted connections after the traffic had died down

17

Hmm, maybe it did. Hard to say

18

I was kind of panicking haha, but I believe some connections did go through

19

Thanks!

20 
root@kproxy1:/var/log# systemctl show kumoproxy.service | grep -E 'LimitNOFILE|LimitNPROC|TasksMax'
TasksMax=infinity
LimitNOFILE=2097152
LimitNOFILESoft=2097152
LimitNPROC=200000
LimitNPROCSoft=200000
21

Should be better now