TCP and UDP service ports don't work

Questions / Help
1

I followed the steps in the following article to create a service that uses TCP and UDP ports:

in fact, I just cloned the example repository and deployed it:

However, it doesn’t seem to work. When I attempt to throw some packets at it, netcat just times out:

[penberg@turing iku-turso]$ echo hello world | nc penberg-echo-test.fly.dev 5000
Ncat: TIMEOUT.

I can ssh to the machine and see that there app is there listening:

root@fbe46807:/# lsof|grep 5000
udp-echo  525               root    3u     IPv4               4426      0t0    UDP fly-global-services:5000 
udp-echo  525               root    7u     IPv6               4430      0t0    TCP *:5000 (LISTEN)
udp-echo  525 526 udp-echo  root    3u     IPv4               4426      0t0    UDP fly-global-services:5000 
udp-echo  525 526 udp-echo  root    7u     IPv6               4430      0t0    TCP *:5000 (LISTEN)
udp-echo  525 527 udp-echo  root    3u     IPv4               4426      0t0    UDP fly-global-services:5000 
udp-echo  525 527 udp-echo  root    7u     IPv6               4430      0t0    TCP *:5000 (LISTEN)
udp-echo  525 528 udp-echo  root    3u     IPv4               4426      0t0    UDP fly-global-services:5000 
udp-echo  525 528 udp-echo  root    7u     IPv6               4430      0t0    TCP *:5000 (LISTEN)
udp-echo  525 529 udp-echo  root    3u     IPv4               4426      0t0    UDP fly-global-services:5000 
udp-echo  525 529 udp-echo  root    7u     IPv6               4430      0t0    TCP *:5000 (LISTEN)

and I can verify that the echo app is indeed working:

root@fbe46807:/# nc 127.0.0.1 5000
hello
hello
^C
root@fbe46807:/#

Is the example project out-of-date? Is the fly.toml configuration file missing something?

2

You can say that.

IPv4 isn’t allocated by default, IPv6 is… But connecting (raw TCP/UDP) over IPv6 also fails when IPv4s aren’t allocated: Announcement: Shared Anycast IPv4 - #17 by Seventhnadir

Allocate an IPv4 (costs $2/mo), and see if the example then works?

flyctl ips allocate-v4 -a <app-name>

3

That indeed fixes the problem. Thanks!

1 Like
4

Oh… hello once again, Pekka. Didn’t realise it was you! ChiselStrike on Fly?

5

Hey! Yeah, we actually already migrated our ChiselNow infrastructure over to Fly already and it worked out really well! Blog post coming soon. And I am indeed now working on doing even more on Fly, but can’t yet share any details :wink:

1 Like