Unable to ping LAN

A

AzTeK

Hi everyone, I encounter a big problem with my lovely FreeBSD 8.0 Release.

Indeed i'm unable to ping other computers in the same subnet as me. I have access to internet, i can ping the office printer (7.50) and the gateway (7.1) but not other machines...

I checked that there is no firewall enabled by default, and it seems not... next I have added PacketFilter with only one rule 'pass all'... no changes.

So I need help around this surprising problem !! :r


The most boring thing is that DNS resolution works great on my subnet, if I ping a computer by its hostname, i see the correct ip ... but no answers...



For information :

ifconfig nfe0:
Code: 
nfe0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
        options=8<VLAN_MTU>
        ether 43:53:60:4d:1a:00
        inet 192.168.7.134 netmask 0xffffff00 broadcast 192.168.7.255
        media: Ethernet autoselect (100baseTX <full-duplex>)
        status: active

netstat -r :
Code: 
Routing tables

Internet:
Destination        Gateway            Flags    Refs      Use  Netif Expire
default            Parefeu            UGS         8    66757   nfe0
localhost          link#5             UH          0     1058    lo0
192.168.7.0        link#3             U           1     1229   nfe0
Vinz               link#3             UHS         0        0    lo0

Internet6:
Destination        Gateway            Flags      Netif Expire
localhost          localhost          UH          lo0
fe80::%lo0         link#5             U           lo0                                                     
fe80::1%lo0        link#5             UHS         lo0                                                     
ff01:5::           fe80::1%lo0        U           lo0                                                     
ff02::%lo0         fe80::1%lo0        U           lo0

cat /etc/rc.conf :
Code: 
hostname="Vinz.xxxxxxxx.fr"                                               
ifconfig_nfe0="DHCP"

pf_enable="YES"           
pf_rules="/etc/pf.conf"
pflog_enable="YES"               
pflog_logfile="/var/log/pf.log"


Ping XA3530.xxxxxx.fr (correct IP found !!) :
Code: 
PING XA3530.xxxxxxx.fr (192.168.7.102): 56 data bytes                                                
ping: sendto: Host is down


Ping broadcast :
Code: 
PING 192.168.7.255 (192.168.7.255): 56 data bytes
64 bytes from 192.168.7.50: icmp_seq=0 ttl=255 time=0.402 ms
64 bytes from 192.168.7.1: icmp_seq=0 ttl=64 time=0.513 ms (DUP!)



Thanks in advance for any idea or trick to solve my problem :f
 
If you can ping the printer and gateway, I'd say that your system is fine.

What OS are the other computers running? Some common OSes (Windows) drop ICMP packets by default because, well, they're big and scary or something. Those OSes don't respond to pings.
 
Usually, the 'host is down' message means that arp can't even get the MAC address of the target system. Are you sure that the machines you're pinging are in fact physically connected?
 
Bonjour :)
Checklist
- firewalls on target computers
- netmasks on them
- ping between 2 of them
- traceroute

If you dont find where is the bug, post results here
 
Also check the arp tables, as DD said not even arp seems to work. No ARP, no IP.

[cmd=]arp -a[/cmd]
(the same command should work on linux, bsd, os-x and windows)

The ARP table is dynamic so if it's empty try and ping a few machines then check the table again. You should get a list of MAC addresses and associated IP addresses. This is layer 2 connectivity. If that doesn't work the layers above it certainly won't work. When layer2 doesn't work move to layer1. Those are the cards, cables etc. All the physical/electrical stuff.

For the time being, just disable PF. As you already found out, there is no firewall running by default on FreeBSD. Get the basics working first, then move onto the firewall.
 
I try to ping Windows, BSD and Linux systems. I can ping only one or two of them this morning (1 Windows && 1 Linux).

I forgot to post the output of arp -a... what a mistake !

arp -a :
Code: 
Vinz.xxxxxxxx.fr (192.168.7.134) at 43:53:60:4d:1a:00 on nfe0 permanent [ethernet]
Cata-PC.xxxxxxxxxx.fr (192.168.7.100) at 00:24:01:eb:1e:a1 on nfe0 [ethernet]
Parefeu.xxxxxxxxxx.fr (192.168.7.1) at 00:16:b6:8a:0a:4c on nfe0 [ethernet]
XA3530.xxxxxxxxxx.fr (192.168.7.102) at 00:15:af:75:32:db on nfe0 [ethernet]
? (192.168.7.255) at (incomplete) on nfe0 [ethernet]

XA3530 is arp resolved, but :
Code: 
PING XA3530.xxxxxxx.fr (192.168.7.102): 56 data bytes                                                
ping: sendto: Host is down


I really don't know what thinking about this... i tried wireshark but nothing wrong apparently... in fact there just is no response.

I saw that there is other couple of other computers which also can't ping each other. I'm beginning to think that it's a problem of our gateway... Very strange.


SirDice said:
For the time being, just disable PF. As you already found out, there is no firewall running by default on FreeBSD. Get the basics working first, then move onto the firewall.
Click to expand...

Okay :stud
 
AzTeK said:
I saw that there is other couple of other computers which also can't ping each other. I'm beginning to think that it's a problem of our gateway... Very strange
Click to expand...
Machines on the same subnet are "directly connected" so the gateway isn't used.
 
Right, this sounds like possible layer 2 issues. Some more tests:
  • On the hosts you're unable to ping, sniff icmp traffic on that end (Wireshark if it's Windows). Are you seeing the echo request at all? How about an echo reply?
  • Install the net-mgmt/arpwatch port, and give it a couple hours to build its initial DB. Then start watching for problems - e.g. multiple hosts using the same IP address.
 
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