Terry I realized that I put a zero there after I hit send, I just didn't send another email correcting myself. The point I was making was that you were correct, and I was attempting to show that with the wildcard mask.
//s Terry Slattery <[email protected]> wrote: Steve, That matches the 10.20.4.0 subnet and 10.30.4.0 subnet, but it won't match any hosts on either subnet, because the last octet is 0 and the wild-card bits are zero (must match). I was looking for a wildcard mask of 0.10.0.255 to match all hosts on either subnet. If you went further, you could have also come up with 0.255.0.255, to match 10.x.4.x. -tcs On 4/12/11 12:15 AM, Di Bias, Steve wrote: > Terry is right, I may have jumped the gun with the inverse mask statement > (although it's mentioned this way in many documents). For Terry's experiment > let's assume we want to match the voice vlan for buildings 20 and 30 > (10.20.4.0 and 10.30.4.0). By breaking this down into binary and using AND/OR > logic we can easily come up with our answer > > 00001010.00010100.00000100.0000000 > 00001010.00011110.00000100.0000000 > ---------------------------------- > 00001010.00010100.00000100.0000000 = 10.20.4.0 > > 00001010.00010100.00000100.0000000 > 00001010.00011110.00000100.0000000 > ---------------------------------- > 00000000.00001010.00000000.0000000 = 0.10.0.0 > > So the "wildcard" mask to match both buildings would be 0.10.0.0 > > Cheers! > > Thank you. > > Steve Di Bias > Network Engineer - Information Systems > Valley Health System - Las Vegas > Office - 702- 369-7594 > Cell - 702-241-1801 > [email protected] > > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of Terry Slattery > Sent: Monday, April 11, 2011 6:58 PM > To: Jay Taylor > Cc:<[email protected]> > Subject: Re: [OSL | CCIE_RS] offset-list and wild card mask > > Good answer, Jay. For everyone who thinks that the wild-card mask is the > opposite of the subnet mask... > > I have a set of subnets that I need to match. The first octet is 10. The > second octet is a building number. The third octet identifies the subnet in > each building, and is "4" for the voice subnet, which is what I want to match. > > Build a wild-card mask that matches > 10.x.4.x > > Is it the inverse of the subnet mask? > > -tcs > > On 7/22/64 2:59 PM, Jay Taylor wrote: >> Offset list is used to increment the metric of certain routes. >> >> In a wildcard mask a binary 0 means the bit must match and a binary 1 >> means it does not have to match. This is reverse logic compared to a >> normal subnet mask. Also, unlike a subnet mask the 1's and 0's do not >> need to be contiguous. >> >> >> On Mon, Apr 11, 2011 at 11:04 AM, Uli<[email protected]> wrote: >> >>> Hi Expert, >>> >>> Does anyone can explain to me about offset-list as I kind of confused >>> with it. also, in my opinion that wild card mask is reverse of subnet >>> mask, but someone told me it isn't ? >>> >>> >>> Regards >>> _______________________________________________ >>> For more information regarding industry leading CCIE Lab training, >>> please visit www.ipexpert.com >>> >> >> >> > -- Terry Slattery CCIE# 1026 UHS Confidentiality Notice: This e-mail message, including any attachments, is for the sole use of the intended recipient (s) and may contain confidential and privileged information. Any unauthorized review, use, disclosure or distribution of this information is prohibited. If this was sent to you in error, please notify the sender by reply e-mail and destroy all copies of the original message. _______________________________________________ For more information regarding industry leading CCIE Lab training, please visit www.ipexpert.com
