The relays available should be stored in a relay.dat file in the actionsite… Legacy Communities - IBM TechXchange Community
The documentation indicates (http://support.bigfix.com/bes/misc/besclient_icmp.html):
In manual relay selection, the BES Client sends an ICMP packet at the Maximum TTL to BES Relays prior to attempting registration. If the ICMP does not reach a BES Relay the BES Client will not attempt to register with it. If the ICMP ping is successful and the BES Client registers with the BES Relay the hop count determined by the ICMP packet is reported in the Distance to BES Relay property.
During automatic relay selection, the BES Client sends out rounds of ICMP traffic with a constant TTL in each round. Each round of will send an ICMP packet to every BES Relay (BES Relays are listed in the ActionSite’s Relay.dat file). Each round will each use a TTL at a higher value then the previous round, starting at 0 and skipping values at higher TTL values.
This is the most useful post i’ve found regarding troubleshooting relay selection: