Ping not coming trough

[fm045]

I am working on a networking project that involves setting up VLANs, inter-VLAN routing, and OSPF configuration. The goal is to enable communication between devices in different VLANs

I have four PCs, two switches (SW20 and SW30), a multilayer switch (S1), a router (R1), and a new PC (PC72). The devices are connected in a specific way to achieve VLAN segregation

The current challenge is that I'm unable to ping the PCs (PC20 and PC30) from PC72. The goal is to establish communication between PCs in different VLANs

Each PC is in a separate VLAN, and I've configured IP addresses accordingly. The router is involved in inter-VLAN routing, and OSPF is configured for dynamic routing.

I've checked physical connectivity, verified VLAN configurations, and confirmed that the router is set up for inter-VLAN routing. However, attempts to ping PCs from PC72 have been unsuccessful.

There are no error messages, but the ping tests from PC72 to other PCs do not succeed. I've confirmed IP configurations, but communication seems to be blocked.

I would appreciate any guidance or insights on how to troubleshoot and resolve the communication issue between PC72 and the other PCs in different VLANs.

int f0/20= ip add 172.16.1.251/24

Objective
PC72 to ping PC30 and PC20
PC20 to ping PC30

[Joseph W. Doherty]

For starters, compare router interface's IP that connects to switch that connects to PC72 and the latter's IP.

[fm045]

hi,

could you elaborate?

[Joseph W. Doherty]

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@fm045 wrote:

hi,

could you elaborate?

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sw20:

Switch#sh cdp n
Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge
                  S - Switch, H - Host, I - IGMP, r - Repeater, P - Phone
Device ID    Local Intrfce   Holdtme    Capability   Platform    Port ID
R1           Fas 0/1          154            R       C1841       Fas 0/1

R1:

interface FastEthernet0/1
 ip address 172.16.0.254 255.255.255.0

 PC72:

[Joseph W. Doherty]

If my prior post is unclear, look at the two interfaces IP's 3rd octet.

If still unclear, let me know.

[fm045]

So what exactly is the problem and how can I fix it?

[Joseph W. Doherty]

The problem is router's and PC's interfaces are NOT in the same subnet.

The fix is have both in the SAME subnet.

As you're using /24 masks, first 3 octets should match.

[fm045]

I am sorry, I don't think I understand what you mean. All the routers and PC's have the /24 mask and are the same. Could you provide more shots of the problem?

kind regards,

[Joseph W. Doherty]

Correct, subnet masks are /24 and the same, but that's not the issue. It's different network IDs, again, look at 3rd octet of interface IPs.

BTW, @liviu.gheorghe mentions you can change IPs, i.e. "You either change both addresses to 172.16.0.x or 172.16.1.x in order to be on the same subnet and communicate between them."  I believe he overlooked the IP of the router's other interface.  Because of that, I haven't described an actual fix, as I don't know how you intended to assign subnets.

[fm045]

The interface Ips 3rd octets are 0 and 1. Is that maybe what's causing the
ping not to go trough. I have no idea myself.I was told to give int f0/0 ip
addr of 172.16.1.0/24 and int f0/1 172.16.1.0/24. Is there not a way to
still be able to ping the pcs together?

[Joseph W. Doherty]

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@fm045 wrote:
The interface Ips 3rd octets are 0 and 1. Is that maybe what's causing the
ping not to go trough. I have no idea myself.I was told to give int f0/0 ip
addr of 172.16.1.0/24 and int f0/1 172.16.1.0/24. Is there not a way to
still be able to ping the pcs together?

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That's fine, but what were you told for PC72's assignment?

Its network number should agree with the router's interface network number that it connect to.  Currently, it doesn't, which is the cause of your problem.

[fm045]

PC72's assignment was IP address of 172.16.1.1/24.

[Joseph W. Doherty]

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@fm045 wrote:
PC72's assignment was IP address of 172.16.1.1/24.

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Okay, and f0/1 is supposed to be "int f0/1 172.16.1.0/24"?

If so, is it???

[fm045]

yes.
f0/1 is supposed to be "int f0/1 172.16.1.0/24"

[Joseph W. Doherty]

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@fm045 wrote:
yes.
f0/1 is supposed to be "int f0/1 172.16.1.0/24"

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That's fine, but my prior reply also asked, is it.

What does the following show?