public String rebaseHostString(String hostString) {
		String[] split = StringUtils.split(hostString, ",");
		StringBuilder newHostString = new StringBuilder();
		boolean first = true;
		for (String pair : split) {
			if (!first) {
				newHostString.append(",");
			}
			first = false;
			if (pair.startsWith(":")) {
				newHostString.append(pair);
			} else if (pair.contains(":")) {
				newHostString.append(pair);
			} else if (securityEnabled) {
				// When the security mode is enabled, we should provide all IPs
				boolean eachFirst = true;
				for (InetAddress each : NetworkUtils.getIpsFromHost(pair)) {
					if (!eachFirst) {
						newHostString.append(",");
					}
					newHostString.append(pair).append(":").append(each.getHostAddress());
					eachFirst = false;
				}
			}
		}
		return newHostString.toString();
	}
Rebase Host String.. add the missing ip addresses if only host is
provided..

@param hostString host string
@return completed host string.
ngrinder-core/src/main/java/net/grinder/engine/agent/PropertyBuilder.java