Unable to set rule using service name

[Ian Smith]

On Fri, 14 Jul 2017 16:43:56 +0530, Kulamani Sethi wrote:
 > Hi,
 > I want to set a rule for a particular service URL which running on a remote
 > server.
 > I know the IP but don't know the port number where that service is running.
 > If i set rule for IP then it will applied for entire services running over
 > there.
 > 
 > There is a option in IPFW rule we can set either port number or name, but
 > it does not accepting using name. Here is a example for my case.
 > 
 > suppose URL for test1 service  http://x.x.x.x/test1
 >                  URL for test2 service http://x.x.x.x/test2
 > 
 > I tried a rule, "ipfw add 104 deny log  ip from x.x.x.x test1 to any". Got
 > error "ipfw: missing "to'' ".
 > *I want to set rule for test1 where I have no idea about port.*
 > *Also please help me how to know port number if any way is there.*

RW well described (in freebsd-questions@) the relationship between port 
numbers and service names in /etc/services; assuming you know the name, 
that gives you the number.  Are 'test1' and 'test2' real examples, or 
placeholders for real service names?

In any case, you cannot specify a port number in a rule with proto 'ip';
when specifying port/s you need to specify 'udp' or 'tcp' protocol.

Can you give an example of the actual packets (protocol, port number/s) 
that you want to block?

cheers, Ian