What's wrong with ARP? DHCP?

HI ALL,

I have a home network composed of a Windows XP SP2 PC, a Fedora 7
Linux PC and a MFC-8660DN network printer. A linksys switch is working
as a hub for my AT&T DSL modem and my home network. And there is a
"dhcpserver.exe" running as SYSTEM process on the Windows PC; My
"dhclient" task is running on the Linux PC.

At the beginning I downloaded a free dhcp server and assigned an IP
address to MFC printer (since I didn't know how to configure the
Windows dhcp service), After I saw printer got the IP address then I
removed it and the dynamic IP address mysteriously stayed in the
printer until now (I don't know why it doesn't expire, I didn't set it
as permanent).

Problem: Now I found the Windows PC can ping the Linux PC correctly
("ping" from windows) but Linux can't get the ping reply("ping" from
Linux). Then I tried "arping" from Linux PC and eventually I got the
ping reply.

I have added Windows PC's IP and MAC with "arp -s" on my Linux PC
MANUALLY every time when I start Linux. I know it stays in the ARP
cache only. when I use "arp -a" to show all IP links in Linux, I show
two other IP addresses assigned automatically for my switch and my
printer, but not for my Window PC(which is MANUALLY added in).

I have left my Linux firewall open for all the traffic. And Ethereal
on Windows shows pings are sent smoothly in between Linux and Windows
PC.

Question: Should I know in which way I can assign IP to my windows PC
automatically in Windows or Linux? So ping won't fail on Linux.

Answer: ?

Thanks,

Zieger wrote:
> HI ALL,
>
> I have a home network composed of a Windows XP SP2 PC, a Fedora 7
> Linux PC and a MFC-8660DN network printer. A linksys switch is working
> as a hub for my AT&T DSL modem and my home network. And there is a
> "dhcpserver.exe" running as SYSTEM process on the Windows PC; My
> "dhclient" task is running on the Linux PC.
>
> At the beginning I downloaded a free dhcp server and assigned an IP
> address to MFC printer (since I didn't know how to configure the
> Windows dhcp service), After I saw printer got the IP address then I
> removed it and the dynamic IP address mysteriously stayed in the
> printer until now (I don't know why it doesn't expire, I didn't set it
> as permanent).

Well, you will have to reconfigure your printer to have a fixed IP
address (if that is what you need it to have).

>
> Problem: Now I found the Windows PC can ping the Linux PC correctly
> ("ping" from windows) but Linux can't get the ping reply("ping" from
> Linux). Then I tried "arping" from Linux PC and eventually I got the
> ping reply.
>
> I have added Windows PC's IP and MAC with "arp -s" on my Linux PC
> MANUALLY every time when I start Linux. I know it stays in the ARP
> cache only. when I use "arp -a" to show all IP links in Linux, I show
> two other IP addresses assigned automatically for my switch and my
> printer, but not for my Window PC(which is MANUALLY added in).

If you have to run arp by hand, then there is something wrong with your
network!

You need to have one and only one DHCP server on your network; otherwise
you will have IP addressing problems.

>
> I have left my Linux firewall open for all the traffic. And Ethereal
> on Windows shows pings are sent smoothly in between Linux and Windows
> PC.
>
> Question: Should I know in which way I can assign IP to my windows PC
> automatically in Windows or Linux? So ping won't fail on Linux.
>
> Answer: ?
>
> Thanks,
>

Are you running some kind of firewall on your Windows PC? If so, switch
it off.

Robert

Zieger <(E-Mail Removed)> wrote:
> I have a home network composed of a Windows XP SP2 PC, a Fedora 7
> Linux PC and a MFC-8660DN network printer.

For a small home network, I would just assign static IP addresses to each of
the devices.

Mark.

--
Mark Hobley
393 Quinton Road West
QUINTON
Birmingham
B32 1QE

Email: markhobley at hotpop dot donottypethisbit com

http://markhobley.yi.org/

Thanks Robert,

I have to say the IP address assigned to Printer is fixed now (without
DHCP it sticks there until now).

My biggest concern is why "arping" works but "ping" doesn't work in
linux?

-Zieger

Mark,

Why I use DHCP instead of fixed IP is because the network printer runs
a DHCP client and that's the only way to assign a IP address to it. I
think.

-Zieger

> My biggest concern is why "arping" works but "ping" doesn't work in
> linux?
-Were you able to ping the Windows pc from Linux when you configured
the Windows pc mac manually on Linux?
-From my experience I found some Windows pcs don't respond to ping and
I didn't check why because I found those pcs can work fine inside the
lan and can reach the Internet, May there is error with afirewall
installed on Windows and prevent the echo-reply to get out.
-If ping doesn't work with you some times try Nmap for example to see
if there any wrongs may you have arp poisoning because of avirus for
example or some thing else, Because Nmap can ping without ICMP
actually if you configured it this way and it doesn't get affected
with arp poisoning anyway and I am sure, To scan apc using Nmap
without ICMP issue some thing like this,
nmap -P0 192.168.1.1