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One physical site with 2 subnets

Posted on 2014-11-18
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Last Modified: 2014-11-30
Hi there,
Running server 2008 ent R2 domain with 2 DC server 2008 and one  DC server 2012 ent datacenter all clients windows 8.1 x64.  On my physical site I was running 2 subnets 10.10.10.0/24 and 10.10.2.0/24.  Things were working fine. Till yesterday any computer attaining IP from subnet 10.10.2.0/24 is really really slow logging in, and the same computer would act accessing the network resources.  I also tried to rejoined to domain the computer which already had 10.10.2.0/24 IP, it says the domain does not exist.
Steps:
-I manually put the IP from subnet 10.10.10.0/24 and restarted the machine things were very well, no lagging while logging on, can access the network resources etc.
-I disabled the scope for 10.10.2.0/24 under superscope of DHCP server and re-added just to make sure the problem goes away, the problem persist while any computer gets the IP from this subnet.

I had no issues before.  This problem appeared recently.  Could it be the new DC server 2012 doing something odd?

Need help with this odd problem.
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Question by:amanzoor
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16 Comments
 

Accepted Solution

by:
KinnyAdelaide earned 300 total points
ID: 40451533
Have you modified the router configurations recently? or checked if there is a problem with routing? I dont think its a layer 2 issue, could be layer 3 issue. Top of my mind, i can draw out other possibilities. But interesting, let me know the conclusion.
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Assisted Solution

by:nader alkahtani
nader alkahtani earned 100 total points
ID: 40451686
pathping command may help you to see where is the problem http://technet.microsoft.com/en-us/library/cc787365(v=ws.10).aspx
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Assisted Solution

by:bominthu
bominthu earned 100 total points
ID: 40451820
Are you able to ping DNS server (10.10.10.xxx) from 10.10.2.0/24 ?

I think it is routing/access-list issue between 10.10.2.0/24 and 10.10.10.0/24.
You need to look at your router or firewall setting.
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Author Comment

by:amanzoor
ID: 40454021
Kinny,
No changes in router were made.
Nadir,
Pingpath is fine even if the machine attains an IP from 10.10.2.0/24
Bominthu;
Yes I am able to ping the DNS and even the DHCP from the machine with IP 10.10.2.0/24

Guys its the really really slowness from this subnet.  Amazingly if I assign static IP from 10.10.10.0/24 the machines boost up with no slowness.
I thought DHCP logs would tell me something, but the funny thing is the machine gets the IP from 10.10.2.0/24 but after a long delay.  I had already removed any antivirus and firewalls from DHCP and the client to set aside the possible cause.
I am totally out of ideas.  Need help
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Expert Comment

by:KinnyAdelaide
ID: 40454069
DNS not looking up the DNS server properly. Maybe there is a fault in the records? Try capturing the packets from DNS and dhcp.
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Author Comment

by:amanzoor
ID: 40455531
Guys,
I corrected the sites and services with correct subnet it should be 10.10.2.0/23, I made a new scope under DHCP for 10.10.2.0/23.  Things work now my clients in 10.10.2.0/23 cannot access files from my server in 10.10.10.0/24.  Help me to configure routing on my switch please.
For now, I have put 2 IPs on my file server and DC to work so that my clients can access the files;
i.e 10.10.10.11 and 10.10.2.11.  But I do not want my DC to be multihomed.  Need help
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Expert Comment

by:KinnyAdelaide
ID: 40456905
Can u show us a topology of your network? Maybe one of us can accurately tell you what route is needed at which device. I think a static default route is needed on the switch. Would be  a good idea to show us your switch's routing table.
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Author Comment

by:amanzoor
ID: 40457307
Kinny,
Attached is the show run from my brocade, will showrun, vlan, and route from a client (windows8.1)  On my brocade I did not find any show ip route.
brocade6450.txt
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Author Comment

by:amanzoor
ID: 40457320
Topology:
Cisco2911 ............>>>brocade 6450.........>>>>clients     (very simple)
router                           switch                                win8.1
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Expert Comment

by:KinnyAdelaide
ID: 40457380
In your IPV4 route on client. I can only see the 2.0 network with /23. Whereas your switch is in 10.0 network. I think your client needs a route to 10.0 network, /24, DGW to router interface. Next setup a IP route 0.0.0.0 0.0.0.0 {interface type & number to the router}. Right now I think link fault lies between your client and switch. Any other expert  thinks so too?
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Author Comment

by:amanzoor
ID: 40457456
Here is the show ip route from my cisco 2911 router:
router_2911#show ip route
Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGP
       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
       E1 - OSPF external type 1, E2 - OSPF external type 2
       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
       ia - IS-IS inter area, * - candidate default, U - per-user static route
       o - ODR, P - periodic downloaded static route, + - replicated route

Gateway of last resort is xx.xx.xx.xxx to network 0.0.0.0

S*    0.0.0.0/0 [1/0] via xx.xx.xx.xxx
      10.0.0.0/8 is variably subnetted, 6 subnets, 3 masks
C    10.10.2.0/23 is directly connected, GigabitEthernet0/0  <<<<.......if this is here why am I not able to see shared folders from 10.10.10.0/24?
L        10.10.3.254/32 is directly connected, GigabitEthernet0/0
C        10.10.10.0/24 is directly connected, GigabitEthernet0/0
L        10.10.10.254/32 is directly connected, GigabitEthernet0/0
C        10.10.11.0/24 is directly connected, GigabitEthernet0/1.801
L        10.10.11.254/32 is directly connected, GigabitEthernet0/1.801
      xx.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C        72.xx.xx.xxx/28 is directly connected, GigabitEthernet0/1.420
L        72.xx.xx.xxx/32 is directly connected, GigabitEthernet0/1.420
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Author Comment

by:amanzoor
ID: 40457474
Hi Kenny,
*************
In your IPV4 route on client. I can only see the 2.0 network with /23. Whereas your switch is in 10.0 network. I think your client needs a route to 10.0 network, /24, DGW to router interface. Next setup a IP route 0.0.0.0 0.0.0.0 {interface type & number to the router}. Right now I think link fault lies between your client and switch. Any other expert  thinks so too? *
*************************************************************
You are correct.  At this time my client(wind 8) can only access a server under 10.10.10.0/24 unless I put an IP from 10.10.2.0/23 on that server.  Some route etc needs to be put into brocade switch.  Where and how I need help.
Thanks
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Author Comment

by:amanzoor
ID: 40457610
Hi,
On the router what does this access 23 mean:
access-list 23 permit 10.10.10.0 0.0.0.7
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Expert Comment

by:nader alkahtani
ID: 40457636
That standard access list number 23 applied permit to subnet 10.10.10.0/29 255.255.255.248
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Author Comment

by:amanzoor
ID: 40457726
Nadir,
Does this access list allows my 10.10.10.0/24 and 10.10.2.0/23 subnets?  By looking at the 23 I am assuming my 10.10.2.0/23 is not allowed.  Can I put:
-access list 23 permit 10.10.2.0/23 255.255.253.254 ?  Need help
Thanks
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Author Comment

by:amanzoor
ID: 40457762
Hi,
I can ping all my servers in subnet 10.10.10.0/24 from client with 10.10.2.61/23 address but cannot access shared folders unless I assign two IP's to that server, one from each subnet.
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