You may be having problems getting AppleSearch Server v1.5 to work properly with network firewalls. Since the AppleSearch Server v1.5 does WAIS communications, it should be set it up as a WAIS connection when configuring the network firewall.
About Firewalls
---------------
Firewalls are not as static and immutable as the name suggests. They are essentially filters that look for particular types of network traffic and allow or disallow the packets to proceed, accordingly. Internet services identify themselves by a port or socket number which is attached to each packet. These packets are usually what firewalls look at with their filters.
WAIS operates on socket 210, so when the network administrators configure the firewall, they can allow 210 traffic to pass. This allows WAIS and the AppleSearch Server v1.5 to work correctly within network firewalls.