Only if the IP addressing was using "classful" addresses from RFC 791 could you know the subnet mask without it being explicit. When it does, the high order network bits will determine the mask. (This also assumes no subnetting.)
Perhaps if origical poster could elaborate a bit more in terms of who is giving the IP address would probably help, but plain and simple as others have indicated it is hard to tell the mask by looking at a single IP address alone, think of this, much like a home address without specifying CITY STATE.
Thanks to all for your responses. I inherited a network from a prior engineer and I was in the process of analyzing the network diagrams. The network diagrams don't show the subnet mask but only show the IP address, so that's why I was inquring about a way of finding the subnet mask based on the IP address only.
Understandable and I see your point, most of us Im sure usually use in diagrams at least I do the mask in bits represented in its decimal value /23 /24 etc..
but in the case of trying to verify which networks are in placed/advertized is looking at routing tables on companies central CORE router, routing tables would definately provide mask information for all your private networks.
This is actually a pretty cool feature, i didn't even know it existed until I was looking for a solution to advertise a subnet (prefix in BGP talk), only if a certain condition existed. This is exactly what conditional advertisements does
j ai une question j ai achete un routeur cisco 887VA-k9 , je le configuré avec la configuration ci- dessous
si je le lier avec mon pc portable sur l un de ses ports directement ça marche toute est bien ( la connexion internet + m...
Attached policy provides CLI access to the Cisco 4G router over text messaging. Two files are in the attached .tar file:
2. PDF with instructions on how to load and use the .tcl file.