Check your pg_hba.conf file.

On the master($HOST1) it should contain
host    all         all         192.168.1.24     255.255.255.0     trust

and on the slave($HOST2) it should contain
host    all         all         192.168.1.22     255.255.255.0     trust

This is covered in 
System Requirements
3.4. Network Connectivity

It is necessary that the hosts that are to replicate between one another
have bidirectional network communications between the PostgreSQL
instances. That is, if node B is replicating data from node A, it is
necessary that there be a path from A to B and from B to A. It is
recommended that, as much as possible, all nodes in a Slony-I cluster
allow this sort of bidirection communications from any node in the
cluster to any other node in the cluster