Unable to ping

[jferraro]

We are on a network of five computers. I can map from one computer to another and it works fine.

I am unable to ping by IP address from anyone one computer to another though.

This is causing a problem because our network backup software uses IP addresses to backup the computers. It was working before, but now it is unable to find any computer on the network.

I am able to successfully ping the printers on the network though.

Any idea what is going on here??

Thanks.

[TechGeek]

Make sure all the computers are connected to the network and make sure their IP hasn't changed.

[midsail]

Checj your submask setting, it should look something like 255.255.255.x Also ip adress scheme, something like 192.168.1.x It sounds like a router configuration. check the router settings. Let us know.

[jferraro]

IP addresses and subnet masks are correct.

[dahlarbear]

1.  Firewall.  If the computers have software firewalls, check their settings.  If I remember correctly "ping" is part of the Internet Command Message Protocol (ICMP).  Ensure each firewall allows both the "incoming" ping and the "outgoing" response.

I not sure it's listed as "ping".  Might be listed as ICMP "echo request" and "echo response" messages.  See the following Wikipedia article:  PING.

2.  Operating System.  What operating systems and service pack levels are you working with?

[midsail]

If u can map Meaning connect by PC name your NETBIOS is working. Trying checking the WINS setting. Also do a ipconfig /all in a command prompt window. let us known what the outcome is.

[jferraro]

Ok, it seems to be something related to the Personal Firewall portion of the Trend Micro Internet Security software we are using because when I disable the Firewall portion, I am able to ping. Problem is I don't know what setting in the Firewall to change to allow it to ping with having to disable the Firewall altogether.

[dahlarbear]

This link should help:  How do I allow or block specific ICMP message types in Trend Micro Internet Security 2009?

They don't appear to make it easy.  The two ICMP messages you're looking for per their nomenclature are "Echo Request" (the incoming ping) and "Echo Reply" (the outgoing ping response).  Some of the ICMP message types from the above link:

Problem:  You can set Trend Micro Internet Security to allow or block any of the following ICMP message types:

    0 Echo Reply
    3 Destination Unreachable
    4 Source Quench
    5 Redirect Message
    8 Echo Request
    9 Router Advertisement
    10 Router Solicitation
    11 Time Exceeded
    12 Parameter Problem
    13 Timestamp
    14 Timestamp Reply
    15 Information Request
    16 Information Reply
    17 Address Mask Request
    18 Address Mask Reply
    30 Traceroute
    37 Domain Name Request
    38 Domain Name Reply