What is happening when I ping against firewall?

Thank you Steven for your prompt and helpful response. Even though English may not be your first language, I can understand it perfectly well and, if you don't mind my saying, it's infinitely better than if I tried your

*first* language (which I suspect is one of the many Oriental languages!).

I've spoken with my friend since posting and he told me that his XP firewall has the following checked in the Advanced Settings:

13737 UDP 8679 TCP

so I wonder if one or both of these are allowing my pings to attract a response. I'm inclined to ask him to uncheck them and then I'll ping him again.

I will ask him to set up the XP Firewall log so we can see what's happening. My router has a facility of responding to, or ignoring, incoming pings so I'll make a swap and ask him to ping me again. There's also a log which I can set up to see what's happening.

Fascinating, this home networking stuff, isn't it????

The reason that the remote guy can't ping him will be simply that his router is not responding to the pings.

An incoming ping won't be passed to the PC, as (unless inbound connection forwarding is specifically set up in the router) there is simply no mapping in the router to tell the router where to send it!

paul

Thanks Paul. I've spoken with Netgear and they're fairly helpful in setting things up but if I ask some related "general enquiry" question, they're not so helpful! I didn't expect a telephone tutorial from them but they could have been a little more receptive! At least the response would have been instantaneous!

I set a log on my router and it did, as expected, identify the incoming pings. The router also has a setting to respond to incoming pings and I checked that, but it didn't do as expected! I haven't found out how to map from the router to the laptop, merely as an academic exercise. I'm heartened by the fact that the router rejects the pings. My pal isn't so fortunate though. He had Printer and File Sharing ticked so we undid that - and his PC still responded to my pings. The XP Pro firewall log identified them.

I hope that someone else has some ideas to try. He hasn't got a router and doesn't see the need for one so it looks like a software setup solution is in order.

Thanks again for your time and patience.

I read in one of Microsoft KB that if file and printer sharing is enabled (I think it is port 445) then automatically ICMP ping is enabled. This can be verified under Windows Firewall (for that particular network adapter, Control Panel, Windows Firewall/Advance/Settting/Advance/Network Adapter/ICMP Tab/Settings/ Allow incoming echo request. A "Tick" to the Allow Incoming Echo Request will allow his computer to be pinged.)

Setting the log file should be fairly simple. Its under the security logging, log drop and successful logging. Default log file can be read using a normal text editor and the location is "c:\\windows\\pfirewall.log"

If he wants to disable ping request, he must ensure that

1. Windows XP Firewall is ON.
2. File and printer sharing is set to disabled.

As for your case, your router or zone alarm might already have ICMP disabled and hence, he can't ping you.

Sorry but I can't seem to remember the Microsoft KB and English is not my first language. I hope you understand what try to convey.

Here are the ports that Micro$oft uses

ping is the ident port 113...I think.

The "ping" command doesn't use a port. It's an ICMP (internet control message protocol) ECHO request.

In Message-ID: posted on Mon, 08 Nov 2004 22:16:59 -0700, DevilsPGD wrote: Begin

Sometimes referred to as port "zero"

Fascinating information - thank you.

Umm you can call it cloud nine if you want, but ICMP doesn't have a port. It's a protocol on the same level as TCP or UDP.

ICMP has a "type" rather then a "port"

ping is on port 3503...I just checked it.

Thanks Steven for the comprehensive instructions - I'll check them out and report back when I've had chance to speak with him.

Thats pretty odd as it worked for me. Once ICMP ping is disabled you shouldn't be able to ping him. Pls check the following;

1. Windows XP Firewall is ON.
2. File and printer sharing is set to disabled.
3. Make sure under Control Panel/Firewall/ICMP Setttngs/Allow Incoming Echo Request is unchecked.
4. Make sure he did not specifically open any ports under Control Panel/Firewall/Exception. (perhaps its a good idea to uncheck all Exception in order to properly test)

Well you could use the firewall log information and specifically block the port under IPsec/TCP filtering but lets not talk about this yet OR get him to install Zone Alarm?

No problem on the help thingy. Just report back so that others can benefit and learn. TQ