How to specify the actual source IP used for connecting to the destination MBP with socks proxy

I have this configuration in my sources.toml:

[source.srv3-s1]
source_address = 'KUMOMTA_SERVER_IP'
ehlo_domain = 'srv3-s1.ahasend.com '
socks5_proxy_server = '185.214.99.2:5000'
socks5_proxy_source_address = '185.214.99.2'
[source.srv3-s2]
source_address = 'KUMOMTA_SERVER_IP'
ehlo_domain = 'srv3-s2.ahasend.com '
socks5_proxy_server = '185.214.99.2:5000'
socks5_proxy_source_address = '185.214.99.3'

# More IPs on the same server...
# Other source definitions...

[pool]
[pool.good]
[pool.good.srv1]
weight = 100

[pool.good.srv2]
weight = 100

[pool.good.srv3-s2]
weight = 1

# Other pool definitions...

The Kumo proxy-server is running at 185.214.99.2:5000 and the server has both 185.214.99.2 and 185.214.99.3 IPs assigned to it (they are being shown in the ip a output on the server and can be pinged from outside).
From what I read in the docs (Routing Messages Via Proxy Servers - KumoMTA Docs) I expected that setting socks5_proxy_source_address to 185.214.99.3 for srv3-s2 would mean that the connection from the proxy server to the MBP would be made from 185.214.99.3 but from what I see in the logs, all the connections are being made from 185.214.99.2 even though I don’t even have srv3-s1 assigned to any pools. Am I misunderstanding how this works?

Hey there @original-baboon, thanks for posting. Please read the “Troubleshooting” and “How to Ask for Help” buttons below. If you would like a 1:1 support session from the KumoMTA team, details are at the “Book a Support Session” button below.

There was a fix for this, what release are you on?

kumod 2024.04.20-4272b4a3

Although I think the proxy-server is older

Was the fix in kumod or the proxy-server?

the proxy server: proxy-server: fix missing bind(2) call · KumoCorp/kumomta@a8b61ce · GitHub