Este pode ser um desafio difícil. A documentação do servidor git faz um trabalho bastante claro de descrever o desafios que você enfrentará configurando isso, incluindo configuração do xinetd :
The Cons
The downside of the Git protocol is the lack of authentication. It’s generally undesirable for the Git protocol to be the only access to your project. Generally, you’ll pair it with SSH or HTTPS access for the few developers who have push (write) access and have everyone else use git:// for read-only access. It’s also probably the most difficult protocol to set up. It must run its own daemon, which requires xinetd configuration or the like, which isn’t always a walk in the park. It also requires firewall access to port 9418, which isn’t a standard port that corporate firewalls always allow. Behind big corporate firewalls, this obscure port is commonly blocked.
A documentação também tem uma seção sobre como iniciar o git como um daemon usando Upstart . xinetd apontaria para esse daemon.
Boa sorte!