2 connected but 1 doesnt! (home networking)

[bilal]

Hi,

Seeking suggestions to resolve the following issue.

My network setup goes this way,

I have 2 desktops and 1 laptop. All 3 connected to switch(not router) and switch is connected to Modem(zyxel). No problem with cables, tcp/ip configuration and firewall(disabled). Adsl connection.

Problem is one desktop manages successful connection but second one does not. It shows that local area is connected but nothing appears in workgroup and internet explorer fails to load any page. I even tested single pc with switch and still no result. What possibly is wrong with 2nd desktop? 1st desktop and laptop are working fine and sharing files through network but 2nd desktop fails to proceed any connection with internet or other computers on network.

Ip assigned : 192.168.0.2,3,4 (2 is not working)
Subnet : 255.255.255.0
Default gateway : 125.209.112.1
Dns : 202.141.224.34 , 202.141.229.34

Following stats found set in web based modem configuration.

WAN Information
- DSL Mode: ADSL_G.dmt
- IP Address: 125.209.112.53
- IP Subnet Mask: 255.255.255.0
- Default Gateway: 125.209.112.1
- VPI/VCI: 0/35
LAN Information
- IP Address: 192.168.1.1
- IP Subnet Mask: 255.255.255.0
- DHCP: Server


Please help me on this issue. What is wrong with 2nd desktop?

Bilal.

[Rick]

Hi,

Ip assigned : 192.168.0.2,3,4 (2 is not working)
Subnet : 255.255.255.0
Default gateway : 125.209.112.1
Dns : 202.141.224.34 , 202.141.229.34

Following stats found set in web based modem configuration.

WAN Information
- DSL Mode: ADSL_G.dmt
- IP Address: 125.209.112.53
- IP Subnet Mask: 255.255.255.0
- Default Gateway: 125.209.112.1
- VPI/VCI: 0/35
LAN Information
- IP Address: 192.168.1.1
- IP Subnet Mask: 255.255.255.0
- DHCP: Server



NOTE the two highlighted above
The address's must Match exactly
192.168.1.N and 192.168.0.N will NOT talk to each other regardless of what Number you put in place of the N


First 3 areas MUST match ALL should be the same 192.168.1.
You have the 3rd setting at 1 on one and 1 in the other

[yawningdog]

What model switch are you using?

[bilal]

thanks for identifying. i observed many strange ip happenings and it is because i made different changes to get some result out of 2nd desktop.

You have the 3rd setting at 1 on one and 1 in the other

I coudnt understand this one on one.

I changed ip addresses as you indicated but no result. 2nd desktop only shows that it is connected but still fails to get internet connection. Other two computers working fine in every strange ip configuration. Would it be a builtin Network card? Should i install external network card to check?

any other suggestions,

Thank you for the response.

Bilal

[bilal]

What model switch are you using?

I am using Repotec, RP-1708K, 8-P 10/100Mbps, NWay Switch.

[Rick]

That was a Typo on my part

it should be
You have the 3rd setting at 1 on one and 0 in the other

One quick way to get your settings correct IF you can get next to each other

Start and run both systems
Decide what the IP for each is/will be
192.168.1.1
and follow that with the others
192.168.1.2
192.168.1.3

OR
192.168.0.1
192.168.0.2
192.168.0.3

Go through each setting matching Everything Except the individual IP for each unit

Using one of the 2 working units as the base point

[yawningdog]

Your default gateway is wrong. It has to be on the same network, that is, the first three octets of the computer's IP and the gateway must match as well. Are you using DHCP or are your IP addresses statically assigned?

[bilal]

That was a Typo on my part

it should be


One quick way to get your settings correct IF you can get next to each other

Start and run both systems
Decide what the IP for each is/will be
192.168.1.1
and follow that with the others
192.168.1.2
192.168.1.3

OR
192.168.0.1
192.168.0.2
192.168.0.3

Go through each setting matching Everything Except the individual IP for each unit

Using one of the 2 working units as the base point

I applied ur mentioned settings but couldnt get 2nd desktop to work.
1st desktop and laptop are surprisingly working in both ip settings.

When 2 computers work and 1 doesnt! How it would be ip setting probelm? I am trying to find a logic behind 1 pc does not work and the rest 2 do.

yawningdog
Your default gateway is wrong. It has to be on the same network, that is, the first three octets of the computer's IP and the gateway must match as well. Are you using DHCP or are your IP addresses statically assigned?

Default gateway is assigned by ISP. DHCP is not enabled. I even tried 192.168.0.1 (universal):( .

[yawningdog]

125.209.112.1 is the gateway assigned to the public side of your modem. Your PCs cannot use it unless they are on the same network, which they are not. Your public IP for your modem is 125.209.112.1 (listed under WAN information) and it uses a gateway of 125.209.112.1. Given a subnet mask of 255.255.255.0 that puts them both on the 125.209.112.0 network. That's how it's supposed to work.

Your modem's private side (under LAN information) has an IP of 192.168.1.1. This should be the gateway of all of your computers, and given a subnet mask of 255.255.255.0 all of your computers should have an IP address of 192.168.1.xxx. Again, this places the computer and gateway on the 192.168.1.0 network.

But...your modem needs to perform NAT, or none of this will work.

[bilal]

Thanks for explaining wan and lan information!

I did all with same result! 1st desktop and laptop works but 2nd doesnt. Why 2nd desktop gives no result when connected to switch alone? What 1st desktop differentiates from 2nd desktop despite having identical hardware platform and operating system?

As u mentioned,

But...your modem needs to perform NAT, or none of this will work.

In short! I need to buy a router? Since switch does not perform NAT!

Thanks for explaining some aspects. I have gained a lot.

Bilal.

[yawningdog]

It sounds like you need a router, but don't rush out and buy one based on what you've seen on this forum. Technically, only one of your other computers should have internet and if I understand you correctly, both of them do.

From the computer that is giving you trouble, try to ping the IP address of one of the other computers that is working. If that works, ping the gateway. If that works, ping the public IP address. And if that works, ping a domain. (www.google.com for example) You need to figure out where in your IP addressing scheme the breakdown is occurring.

Do tell, did you statically assign IP addresses to everything?

[bilal]

2nd desktop fails to ping any of 2 other working pc's. I installed an external network card on 2nd desktop and it started working. There may be some conflict between network cards of both desktops.

I havent plugged in all 3 at a time. But 2 desktops are working.

Your configuration explanation has helped me alot due to which i was enforced to test an external network card because i was confident that there is no problem with network and ip configuration.


Thank you for your time.:)