Ping an IP address with and without a firewall

[Tosca]

Hello everyone

A friend and I each have XP Pro and connect to ADSL. He connects with a
cable and I connect wirelessly. I have a firewall in the router as well as
ZoneAlarm on my laptop. He uses the built-in firewall.

We tried pinging each other's IP address and the response that he got was
that it was timed out and all of the packets were lost. That it what I
expected but, when I looked at the router's and ZoneAlarm's logs, they
didn't report anything unusual. Should anything have been reported?

When I pinged his IP address, the none of the packets were lost. I
contacted him and he told me that his firewall was off (!). He turned it on
and I tried again - with the same result.

I was under the impression that the firewall would reject such things. Is
this correct? What am I missing? Is my understanding of IP addresses and
firewalls flawed? Should he be pleased that my ping attempts got through or
should I be pleased that none of his got through? Does either of us have a
problem with the firewall?

Thanks for your time and patience.

 

[Peter Hutchison]

Hello everyone

A friend and I each have XP Pro and connect to ADSL. He connects with a
cable and I connect wirelessly. I have a firewall in the router as well as
ZoneAlarm on my laptop. He uses the built-in firewall.

We tried pinging each other's IP address and the response that he got was
that it was timed out and all of the packets were lost. That it what I
expected but, when I looked at the router's and ZoneAlarm's logs, they
didn't report anything unusual. Should anything have been reported?

When I pinged his IP address, the none of the packets were lost. I
contacted him and he told me that his firewall was off (!). He turned it on
and I tried again - with the same result.

I was under the impression that the firewall would reject such things. Is
this correct? What am I missing? Is my understanding of IP addresses and
firewalls flawed? Should he be pleased that my ping attempts got through or
should I be pleased that none of his got through? Does either of us have a
problem with the firewall?

Thanks for your time and patience.

If there is more than one firewall, then ICMP events such as Pings
could be blocked at any point. So check the router and wireless
settings again.

Peter Hutchison

 

[Tosca]

Thank you for the prompt response.

Should the ping attempt get through or should all of the packets be lost if
my firewalls (and his single XP firewall) are configured correctly? The
packets to my friend got through but his to me didn't and were all timed
out. Would that suggest a problem with his or my firewall?

 

[Alex Nichol]

We tried pinging each other's IP address and the response that he got was
that it was timed out and all of the packets were lost. That it what I
expected but, when I looked at the router's and ZoneAlarm's logs, they
didn't report anything unusual. Should anything have been reported?

When I pinged his IP address, the none of the packets were lost. I
contacted him and he told me that his firewall was off (!). He turned it on
and I tried again - with the same result.

I was under the impression that the firewall would reject such things. Is
this correct? What am I missing? Is my understanding of IP addresses and
firewalls flawed? Should he be pleased that my ping attempts got through or
should I be pleased that none of his got through? Does either of us have a
problem with the firewall?

The SP2 firewall does not block outgoing messages; only incoming, And in
its Control Panel applet - Advanced page click on ICMP and see what is
permitted - probably incoming echo request (ie ping) is checked as
allowed

In Zone Alarm, Programs page see if TCP/IP Ping command is checked as an
allowed item (system32\ping.exe)

 

[Tosca]

Thank you Alex for the comments. We each have SP1. We've checked ICMP and
nothing is checked on either computer. I've checked my ZoneAlarm and
ping.exe isn't checked or listed as an allowed item.

It seems that this may not be so easy after all!