Mailinglist Archive: opensuse (3336 mails)

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Re: [SLE] SuSE/Linux Ping vs DOS Ping
  • From: Jerry Feldman <gaf@xxxxxxx>
  • Date: Thu, 1 Dec 2005 09:23:53 -0500
  • Message-id: <200512010923.53711.gaf@xxxxxxx>
On Wednesday 30 November 2005 2:11 pm, David McMillan wrote:
> I have a piece of industrial equipment that uses a TCP/IP Ethernet
> interface that I'm trying to troubleshoot at work. Part of the
> manufacturer's troubleshooting checklist is to "connect an DOS/Windows
> computer and use the PING command from the command line." Not having
> a D/W computer handy, I plugged in my SuSE 9.1 Pro laptop, but
> couldn't get a response. Not even a "connection refused," just silence.
> After some fairly exhaustive troubleshooting, this is what we found:
> 1: A DOS ping command, from another computer, using the same IP and
> netmask, over the same cable, got an immediate response.
> 2: The SuSE machine could not get a ping response, but *did* see the
> various open and filtered ports on the inustrial box, on the correct
> IP, when using nmap.
> 3: De/Re-activating SuSE Firewall made no difference.
> 4: The SuSE machine's ping command worked perfectly on a regular
> network, pinging Windows & *nix computers and various hardware routers
> without any difficulty.
> All I can think of is that there must be some minor difference
> between SuSE pings (or perhaps Linux pings in general) and DOS/Win
> pings that doesn't matter to most networks, but *does* matter for some
> reason to this piece of industrial hardware.
> Thoughts?
When Linux pings another host, it sends out the ICMP message and waits for a
response. After some time it should time out.
Check the default route.
Here are some steps you should look at:
1. Make sure your cables are correct.
2. run netstat -nr on your system. You should have a route to the subnet and
a default route. Are you using DHCP or a static IP address? netstat should
look sim,ilar to this.
Kernel IP routing table
Destination Gateway Genmask Flags MSS Window irtt Iface U 0 0 0 eth0 U 0 0 0 eth0 U 0 0 0 lo UG 0 0 0 eth0
3. Are you using a name or an IP address to ping the equipment?
If you are using a name, are you getting a a resolution to that name?
Jerry Feldman <gaf@xxxxxxx>
Boston Linux and Unix user group PGP key id:C5061EA9
PGP Key fingerprint:053C 73EC 3AC1 5C44 3E14 9245 FB00 3ED5 C506 1EA9

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