chris arnold Posted June 4, 2008 Posted June 4, 2008 My IP address ends with a "0". So it is like 54.765.3.0 for example. Someone at work today told me that this is very bad. I used MS DOS with command ipconfig to check this and I have also found that websites report this same IP address.What I want to know is, what are the possible reasons of this and the risks posed by it? My connection is broadband through cable with Virgin Media.Thank-you very much if you can help me!
jaclaz Posted June 4, 2008 Posted June 4, 2008 It would be interesting if the guy that made you worry would produce some data to validate this claim."this is very bad" is not considered usually technically a valid argument. I had a co-worker that didn't want DHCP to assign it's PC an IP address ending with 17, as he thought it was bad.....Maybe the claim originated by this kind of problem:http://searchnetworkingchannel.techtarget....1232847,00.htmlhttp://en.wikipedia.org/wiki/IPv4#Addresse...ing_in_0_or_255IP addresses ending with 0 or 255 are not always possible.The only related "bad" thing I can think of is that some peer-to-peer networks had (or still have ) an algorithm to calculate ID "level" that resulted always as "LOW" if IP address ended with 0.jaclaz
TheFlash428 Posted June 4, 2008 Posted June 4, 2008 You coworker's information is probably assuming your network is a "class C" sized subnet (subnet mask of 255.255.255.0) or smaller, and in that case, an IP ending in "0" would be a network ID (not a client ID), as it would be the first IP address of a given range.If you are operating on a larger subnet, however, than this is not necessarily the case. If your subnet mask is 255.255.0.0, for instance, there are about 255 different possible client IPs on that subnet that could end with a zero. I'm not sure about the peer-to-peer network issue jaclaz mentions, but to answer your question:Just because your IP ends in a "0" does not necessarily mean it is unroutable. If you don't have any problems accessing the Internet or other network resources, then I wouldn't worry about it.
chris arnold Posted June 4, 2008 Author Posted June 4, 2008 Thank-you very much. I also rang Virgin Media and they said that there was not an issue. Well that clears that up then. Thanks!
Tripredacus Posted June 5, 2008 Posted June 5, 2008 Indeed, its totally about how the DHCP server is set up. Most admins like to reserve the first group of IPs (say the first 10 or 20 or whatever) for servers and routers and other things. Its easier to remember that all your infrastructure IPs are between .0 and .20 than just randomly assigned all over the place. It is definately possible to set up DHCP to make a .0 available to a computer if it requests it, its just not common practice.
jaclaz Posted June 5, 2008 Posted June 5, 2008 It is definately possible to set up DHCP to make a .0 available to a computer if it requests it, its just not common practice.Do read the given links, we are talking about EXTERNAL IP addresses, given by the ISP, not internal (local intranet) ones.As explained, an ending 0 or 255 is possible or is it not depending on the "class" of subnet.jaclaz
eyeball Posted June 6, 2008 Posted June 6, 2008 (edited) I though 255 and 0 were reserved for unicast and multicast? hmmm..............*Goes off to wikipedia...*EDIT Nope, 255 is reserved for broadcast on the local subnet. Anyone care to shed some light on anything ending in 0? Edited June 7, 2008 by eyeball
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