Slow when access from a particular network

Unanswered Question

Hello all !!! I having this strange issue and I am reaching out for help !!!

I just rolled out a new application and it's running on a Windows 2003 server located at the data center in Ca. And it's working perfectly normal for users at all remote locations, except for this one particular remote location for some reason the response time from the server to this remote location is extremely slow but when I put the users at this remote location on a different subnet then everything works normally so at this point the issue has been isolated to a particular subnet at this remote location. I have checked the WAN and LAN side but not a able to find anything.

Thanks very much in advance !!!


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ohassairi Tue, 02/05/2008 - 02:05
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try a tracert to one PC in the old subnet and an other one in the new subnet and look if they take the same path.

aijaz802 Tue, 02/05/2008 - 02:18
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Try to do trace route from slow subnet and fast subnet and check the path. The ISP might be using different route for this particular subnet.

If you are using NAT, check the nat public IP for any b/w limitations or QOS policies.

Thanks.. Rate if this helps.

Danilo Dy Tue, 02/05/2008 - 06:12
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Without knowing your network architecture, its difficult to see where is the problem.

However, you can look at the following.

- QoS that affect the "problem subnet"

- Overlapping network that affects the "problem subnet"

- Gateway interface of the "problem subnet" (speed/duplex, cabling, etc..)

- If the "problem subnet" is using DHCP, check the DHCP configuration (Gateway, WINS, DNS, SubNet Mask)

- VTP of the problem subnet (check for loop)

- Switches and their interfaces (speed/duplex, cabling, etc..) that connects the "problem subnet"

- Sniff the "problem subnet", a host NIC connected to the same subnet maybe faulty and sending a lot of broadcast.

- Sniff the "problem subnet", a host connected tothe subnet maybe infected with a Virus.



Hi Dandy,

thanks for your response ! I appreciate it very much !! I have checked all the above you mentioned but still not able to see anything. My network layout is quite simple, take a look at below.

servers-->6509-->3825rt-DS3->MPLS wan<-T1-3725rt<--3560switch<--host.

I did a tracert from a host on a working subnet(172.16.53.x/24) and a host on a problem subnet (172.16.52.x/24) to the servers and it took the same path reach the servers. The slowness only occurs between the new app servers and the hosts on 52.x network. I have other servers that reside on the same network as the new app servers and everything works normally users on 52.x network can access these servers with no issues.

Any other suggestions !!!

thanks again !!!


ohassairi Tue, 02/05/2008 - 20:13
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i am afraid the problem is in your server IP settings or other parameters.

compare server config with other servers.

also if you can re-install the server/application....

Danilo Dy Tue, 02/05/2008 - 22:26
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I think you need to perform further isolation.

In your post, both 52.x and 53.x are connected to 3725rt and only 52.x have problem

To isolate any host or switch or router as the problem.

1. Try plugging your laptop directly to 3725rt where the 3560 switch is connected and ping the server, if this is not okay, then the problem is within 3725rt for 52.x configuration. Please post your 3725rt config.

2. If step 1 is okay, try plugging back the 3560 switch without any host connected (or shutdown all the switch interface connected to 52.x hosts). Plug your laptop to the 3560 switch using an IP address from 52.x network and ping the server, if this is not okay, then the problem is within 3560 switch for 52.x configuration. Please post the switch and router config.

3. If step 1 and 2 is okay, try plugging 52.x host one at a time (or unshut the switch interface connected to 52.x hosts one at a time while performing ping from your laptop) as one of the hosts maybe creating the problem.




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