firewall rules for SQL Server

If we are doing a 1-way replication from a SQL Server 2000 (Publisher) 
through a firewall to a SQL Server 2005 (Subscriber), do any ****ts need 
to be opened from the Subscriber back to the Publisher?  That is, we 
have 1433, 1434 opened outgoing from the Publisher to Subscriber but for 
successful communications, do any ****ts have to be opened the other way?

Sorry, I'm new to this.

Thanks,
Mike H.