260 2 0 0 0 - A 2 - G B 2 3 - 0 0ExamplesThe quick option is good for rules such asblock in quick from any to any with ipoptswhich will match any packet with a non-standard header length (IP optionspresent) and abort further processing of later rules, recording a match and alsothat the packet should be blocked.The "fall-through" rule parsing allows for effects such as this:block in from any to any port < 6000pass in from any to any port >= 6000block in from any to port > 6003which sets up the range 6000-6003 as being permitted and all others beingdenied. Note that the effect of the first rule is overridden by subsequent rules.Another (easier) way to do the same is:block in from any to any port 6000 <> 6003pass in from any to any port 5999 >< 6004Note that both the "block" and "pass" are needed here to effect a result as afailed match on the "block" actionpass in quick from any to any port < 1024would be needed before the first block.Dial PlanThe Call Agent can ask the gateway to collect digits dialed by the user. Thisfacility is intended to be used with residential gateways to collect the numbersthat a user dials; it can also be used with trunking gateways and accessgateways alike, to collect access codes, credit card numbers and othernumbers requested by call control services.One procedure is for the gateway to notify the Call Agent of each individualdialed digit, as soon as they are dialed. However, such a procedure generates alarge number of interactions. It is preferable to accumulate the dialed numbersin a buffer, and to transmit them in a single message.The problem with this accumulation approach, however, is that it is hard forthe gateway to predict how many numbers it needs to accumulate beforetransmission. For example, using the phone on our desk, we can dial thefollowing numbers:
