/16 & /30 overlap

Hans Bricks

Hi,

Basically I have two subnets on one router. 192.168.0.0 /16 & 192.168.3.8 /30

192.168.0.1 255.255.0.0 is configured for port fa0/0 on the LAN and when I try configure 192.168.3.9 255.255.255.252 on port serial0/0/0 on a WAN link, both overlap with each other.

Any advice on how to fix this ?

Cuddlesworth

Don't use conflicting subnets, put a 10 or 172 private address on your link. Also get a handle on your sub-netting assignment, why in gods name would you assign a /16 anywhere? If your Ip assingment is within a specific range, then work on getting a /22-/24 on the current 192 range.

Hans Bricks

Cuddlesworth wrote: »

Don't use conflicting subnets, put a 10 or 172 private address on your link. Also get a handle on your sub-netting assignment, why in gods name would you assign a /16 anywhere? If your Ip assingment is within a specific range, then work on getting a /22-/24 on the current 192 range.

I can't use 172. I have only one address range to work with. 192.168.0.0 /16

It's a college assignment in Cisco Packet tracer. Basically I have the 192.168.0.0 /16 address range to start off with and I use VLSM from there on in. The first LAN requires 254 hosts so the next VLSM subnet is 192.168.1.0 /24 etc ...
This ends up at 192.168.3.16 /30 when calculating the WAN links in a frame relay private network with 3 separate LANs. One of which I'm using on the same router as the /16 LAN address range.

I've read online that just assigning 255.255.255.0 to the first subnet of /16 instead of 255.255.0.0 should work. What do you think ?

ED E

1. This is CCNA, just google the lab code for a solution :pac:
2. Go ahead and post the full description at least, not enough there to be sure whats required.

Hans Bricks

ED E wrote: »

1. This is CCNA, just google the lab code for a solution :pac:
2. Go ahead and post the full description at least, not enough there to be sure whats required.

I've been googling all day ! I may or may not have solved it actually. One of the forums said that by using the /24 subnet mask for both, that it should work fine.

Cuddlesworth

I would say that regardless, this lab would be taking what you learned from a subnetting lesson and putting it into practise. And you have not learned subnetting or you wouldn't be asking these questions.

You really need to go back and learn what it is and how it works. This is really important to the CCNA or to any future networking. Its the equivalent of starting school and not bothering with the alphabet.

Hans Bricks

Cuddlesworth wrote: »

I would say that regardless, this lab would be taking what you learned from a subnetting lesson and putting it into practise. And you have not learned subnetting or you wouldn't be asking these questions.

You really need to go back and learn what it is and how it works. This is really important to the CCNA or to any future networking. Its the equivalent of starting school and not bothering with the alphabet.

I'm in 4th year. I've been subnetting at least three years now. If I couldn't subnet I wouldn't be where I am right now. I just came to ask for some advice.

Anyway, back to the OP, should I keep using the 255.255.255.0 mask for both network addresses ? Even the /16 ?

moc moc a moc

Hans Bricks wrote: »

should I keep using the 255.255.255.0 mask for both network addresses ? Even the /16 ?

This makes absolutely no sense. As Cuddlesworth says above, you need to review your subnetting. No point in telling us you've been doing it for three years if you're doing it wrong after all this time.

Hans Bricks

moc moc a moc wrote: »

This makes absolutely no sense. Evidently you have been subnetting incorrectly for three years.

I've never encountered this issue before in terms of having to use two separate class of networks on the one router. Hey, thats the advice a professional gave on one of the forums I was reading. I'm genuinely confused here.

ED E

Snotty response and clearly incorrect as above.

Cuddle is right, this is bread and butter stuff. You should be dreaming in CIDR notation if you want to work in a networking field.

Hans Bricks

ED E wrote: »

Snotty response and clearly incorrect as above.

Cuddle is right, this is bread and butter stuff. You should be dreaming in CIDR notation if you want to work in a networking field.

So... what would your approach be ? 192.168.0.0 /16 on an fa0/0 interface and 192.168.3.9 /30 on the serial interface, both conflict with each other.

moc moc a moc

Here's a hint: it involves subnetting. The very first reply in this thread practically tells you exactly what to do if you read it carefully.

Hans Bricks

moc moc a moc wrote: »

Here's a hint: it involves subnetting. The very first reply in this thread gave you a big hint here.

I've already subnetted the entire address space.

192.168.0.0 255.255.0.0 - LAN 1
192.168.1.0 255.255.255.0 - LAN 2
192.168.2.0 255.255.255.128 - LAN 3 VLAN 1
192.168.2.128 255.255.255.128 - LAN 3 VLAN 2
192.168.3.0 255.255.255.248 - LAN 3 Management VLAN
192.168.3.8 255.255.255.252 - LAN 1 FR WAN
192.168.3.12 255.255.255.252 - LAN 2 FR WAN
192.168.3.16 255.255.255.252 - LAN 3 FR WAN

Hans Bricks

moc moc a moc wrote: »

Here's a hint: it involves subnetting. The very first reply in this thread practically tells you exactly what to do if you read it carefully.

Yeah I take on board Cuddle's first reply. But I'm restricted to using only the 192.168.0.0 /16 address space. Hence my utter confusion.

Cuddlesworth

Hans Bricks wrote: »

Yeah I take on board Cuddle's first reply. But I'm restricted to using only the 192.168.0.0 /16 address space. Hence my utter confusion.

Your confused and messing up because you lack the very basics. There are at least 4 separate lines in this thread that show a atrocious lack of understanding of the very concept.

And if I answer your question(which is about the easiest thing in the world to me), I would worry you would continue onwards and fall flat on your face later in life.

There are far better people out there to explain it the me, in video format

Hans Bricks

Cuddlesworth wrote: »

Your confused and messing up because you lack the very basics. There are at least 4 separate lines in this thread that show a atrocious lack of understanding of the very concept.

And if I answer your question(which is about the easiest thing in the world to me), I would worry you would continue onwards and fall flat on your face later in life.

There are far better people out there to explain it the me, in video format

You don't need to worry. Is this VLSM correct to you ?

192.168.0.0 255.255.0.0 - LAN 1 - 254 hosts
192.168.1.0 255.255.255.0 - LAN 2 - 254 hosts
192.168.2.0 255.255.255.128 - LAN 3 VLAN 1 - 126 hosts
192.168.2.128 255.255.255.128 - LAN 3 VLAN 2 - 126 hosts
192.168.3.0 255.255.255.248 - LAN 3 Management VLAN - 6 hosts
192.168.3.8 255.255.255.252 - LAN 1 FR WAN - 2 hosts
192.168.3.12 255.255.255.252 - LAN 2 FR WAN - 2 hosts
192.168.3.16 255.255.255.252 - LAN 3 FR WAN - 2 hosts

Cuddlesworth

Hans Bricks wrote: »

You don't need to worry. Is this VLSM correct to you ?

192.168.0.0 255.255.0.0 - LAN 1 - 254 hosts
192.168.1.0 255.255.255.0 - LAN 2 - 254 hosts
192.168.2.0 255.255.255.128 - LAN 3 VLAN 1 - 126 hosts
192.168.2.128 255.255.255.128 - LAN 3 VLAN 2 - 126 hosts
192.168.3.0 255.255.255.248 - LAN 3 Management VLAN - 6 hosts
192.168.3.8 255.255.255.252 - LAN 1 FR WAN - 2 hosts
192.168.3.12 255.255.255.252 - LAN 2 FR WAN - 2 hosts
192.168.3.16 255.255.255.252 - LAN 3 FR WAN - 2 hosts

I'm walking away from this. Good luck in future.

rmacm

Hans Bricks wrote: »

You don't need to worry. Is this VLSM correct to you ?

192.168.0.0 255.255.0.0 - LAN 1 - 254 hosts
192.168.1.0 255.255.255.0 - LAN 2 - 254 hosts
192.168.2.0 255.255.255.128 - LAN 3 VLAN 1 - 126 hosts
192.168.2.128 255.255.255.128 - LAN 3 VLAN 2 - 126 hosts
192.168.3.0 255.255.255.248 - LAN 3 Management VLAN - 6 hosts
192.168.3.8 255.255.255.252 - LAN 1 FR WAN - 2 hosts
192.168.3.12 255.255.255.252 - LAN 2 FR WAN - 2 hosts
192.168.3.16 255.255.255.252 - LAN 3 FR WAN - 2 hosts

Tis not correct...as many others have mentioned go back and review subnetting again. Your mistake is in the first line (LAN 1).

Hans Bricks

rmacm wrote: »

Tis not correct...as many others have mentioned go back and review subnetting again. Your mistake is in the first line (LAN 1).

Thanks. I changed that to 255.255.255.0. I think I realize now why it becomes a /24 in the first subnet mask.

rmacm

If you want to end up working with networks then I'd say you should be certain about why you are using a /24...seriously you should be doing subnetting in your dreams

moc moc a moc

Hans Bricks wrote: »

Thanks. I changed that to 255.255.255.0. I think I realize now why it becomes a /24 in the first subnet mask.

Only took you three years!

Hans Bricks

moc moc a moc wrote: »

Only took you three years!

Thanks for the support

moc moc a moc

Hans Bricks wrote: »

Thanks for the support

Ah now, you set yourself up for that one to be fair.