Solved

Networking issue

Posted on 2015-01-20
10
96 Views
Last Modified: 2015-01-21
We have a vlan 11 with a DHCP range of 10.11.20.1 - 10.11.254.254 default gateway of 10.11.0.1.

all clients that have an IP address of 10.11.0.x and work fine. All clients that get an IP of 10.11.1.x cannot ping anything (server, gateway, printers, not internet) or be pinged. All client on vlan11 have the same default gateway.

We have a Cisco firewall and cannot find any settings that could be causing this issue. Of course I could be overlooking something.

Not sure if the core switch would do anything. DHCP and DNS are controlled by a windows 2008 DC.

Any ideas?
0
Comment
Question by:bbayachek
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 5
  • 4
10 Comments
 
LVL 34

Expert Comment

by:Paul MacDonald
ID: 40559988
What subnet mask are you using?
0
 
LVL 1

Author Comment

by:bbayachek
ID: 40560000
255.255.248.0
0
 
LVL 1

Author Comment

by:bbayachek
ID: 40560009
I think you are on to something. Should we use 255.255.0.0? If so, it is greyed out in the DHCP settings on our windows dc
0
Optimum High-Definition Video Viewing and Control

The ATEN VM0404HA 4x4 4K HDMI Matrix Switch supports 4K resolutions of UHD (3840 x 2160) and DCI (4096 x 2160) with refresh rates of 30 Hz (4:4:4) and 60 Hz (4:2:0). It is ideal for applications where the routing of 4K digital signals is required.

 
LVL 34

Expert Comment

by:Paul MacDonald
ID: 40560026
You can't change it, I believe, once you've established the DHCP Scope.  You have to re-create it.
0
 
LVL 1

Author Comment

by:bbayachek
ID: 40560063
that's not going to be fun. Would we use 255.255.0.0?
0
 
LVL 34

Expert Comment

by:Paul MacDonald
ID: 40560082
"Would we use 255.255.0.0?"
I can't answer that question for you.  It seems like it would be valid for you, but whether or not it's the best choice...

If creating a new scope is too much trouble, you can create a superscope instead and proceed that way.
0
 
LVL 1

Author Comment

by:bbayachek
ID: 40560142
i just looked at the settings we are using on a IP address calc.

The subnet mask that we are using should be fine. It has a range of 10.11.0.1 - 10.11.7.254
0
 
LVL 1

Author Comment

by:bbayachek
ID: 40560458
ok I found the issue. It was our settings in our core switch. VLAN11 is using subnet mask 255.255.255.0. My new question is if I change the vlan 11 subnet mask to 255.255.248.0 on the core switch would it cause any issues with the devices that are already connected? Will it change the settings in all my other switches?
0
 

Accepted Solution

by:
Jagrenet earned 250 total points
ID: 40560499
If you change the subnet mask to 255.255.248.0 it should not affect any of the devices that are already connected. When the DHCP lease expires, the devices will get a new IP address with the new subnet mask and connectivity should remain seamless to the end user. Obviously, this means changing the subnet mask in the DHCP scope as well.

Your next question, "Will it change the settings in all my other switches? ". This depends .... are you using VTP (VLAN trunking protocol) in your environment? If so, how is it configured? - (i.e Server, Client or Transparent mode)

How many IP Addresses do you have configured for VLAN11 (on separate SVI's)?
We need a little more info.
0
 
LVL 34

Assisted Solution

by:Paul MacDonald
Paul MacDonald earned 250 total points
ID: 40561905
"ok I found the issue."
Great!  And as noted, there shouldn't be any consequences to changing the mask.
0

Featured Post

Independent Software Vendors: We Want Your Opinion

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

For many of us, the  holiday season kindles the natural urge to give back to our friends, family members and communities. While it's easy for friends to notice the impact of such deeds, understanding the contributions of businesses and enterprises i…
Let’s face it: one of the reasons your organization chose a SaaS solution (whether Microsoft Dynamics 365, Netsuite or SAP) is that it is subscription-based. The upkeep is done. Or so you think.
This video gives you a great overview about bandwidth monitoring with SNMP and WMI with our network monitoring solution PRTG Network Monitor (https://www.paessler.com/prtg). If you're looking for how to monitor bandwidth using netflow or packet s…
NetCrunch network monitor is a highly extensive platform for network monitoring and alert generation. In this video you'll see a live demo of NetCrunch with most notable features explained in a walk-through manner. You'll also get to know the philos…

717 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question