Login or Register to Ask a Question and Join Our Community


IP Networking

Two Servers via ethernet crossover cable

Login to Discuss or Reply to this Discussion in Our Community

 
Thread Tools Search this Thread
Special Forums IP Networking Two Servers via ethernet crossover cable
# 1  
Old 05-06-2010
Two Servers via ethernet crossover cable
Hi,

I'm trying to communicate two servers (HP DLProliant 380 G5) via a crossover cable, but I don't get them to ping each other.

I am working in RHEL 4.

These are the steps I've performed:

1) Plugged the crossover cables in eth2.
(note: The cable is brand new. Also I built one myself and the behaviour is the same.)

2) I have configured the interfaces in both servers as follows:

Server1:

Code:
# cat /etc/sysconfig/network-scripts/ifcfg-eth2
DEVICE=eth2
ONBOOT=NO
BOOTPROTO=static
IPADDR=192.168.101.1
NETMASK=255.255.255.0
NOZEROCONF=yes
HWADDR=00:24:81:7D:5E:61
TYPE=Ethernet

Server2:
Code:
cat /etc/sysconfig/network-scripts/ifcfg-eth2
DEVICE=eth2
ONBOOT=NO
BOOTPROTO=static
IPADDR=192.168.101.2
NETMASK=255.255.255.0
NOZEROCONF=yes
HWADDR=00:24:81:7D:62:3D
TYPE=Ethernet

3) I restart the interfaces in both servers: ifdown eth2 / ifup eth2

See green LED on both sides (not blinking but fixed)

4) ifconfig output:

Server1:

Code:
eth2      Link encap:Ethernet  HWaddr 00:24:81:7D:5E:61
          inet addr:192.168.101.1  Bcast:192.168.101.255  Mask:255.255.255.0
          UP BROADCAST MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:0 (0.0 b)  TX bytes:0 (0.0 b)
          Base address:0x5000 Memory:fdbe0000-fdc00000


Server2:

Code:
eth2      Link encap:Ethernet  HWaddr 00:24:81:7D:62:3D
          inet addr:192.168.101.2  Bcast:192.168.101.255   Mask:255.255.255.0
          UP BROADCAST MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:0 (0.0 b)  TX bytes:0 (0.0 b)
          Base address:0x5000 Memory:fdbe0000-fdc00000



5)The routes are taken into account:

In both servers:

Code:
# netstat -nr
Kernel IP routing table
Destination     Gateway         Genmask         Flags   MSS Window  irtt Iface
192.168.101.0   0.0.0.0         255.255.255.0   U         0 0          0 eth2


6) I try to ping from one to the other but not success at all:

Server1 to Server2:
Code:
ping 192.168.101.2
PING 192.168.101.2 (192.168.101.2) 56(84) bytes of data.
From 192.168.101.1 icmp_seq=0 Destination Host Unreachable

Running at same time a tcpdump (in Server1), don't see any traffic over eth2:

Code:
# tcpdump -i eth2
tcpdump: listening on eth2

0 packets received by filter
0 packets dropped by kernel


7) Check the arp but the entry is incompleted (not catch of MAC)

Code:
# arp
Address                  HWtype  HWaddress           Flags Mask            Iface
192.168.101.2                        (incomplete)                              eth2


8) And here is where the issue must be.
I found that ethtool and mii-tool don't agree in the link status. First one indicates it as dow, while mii indicates up.

And here is the output for ethtool and mii-tool:

Code:
# ethtool eth2
Settings for eth2:
        Supported ports: [ TP ]
        Supported link modes:   10baseT/Half 10baseT/Full
                                100baseT/Half 100baseT/Full
                                1000baseT/Full
        Supports auto-negotiation: Yes
        Advertised link modes:  10baseT/Half 10baseT/Full
                                100baseT/Half 100baseT/Full
                                1000baseT/Full
        Advertised auto-negotiation: Yes
        Speed: Unknown! (65535)
        Duplex: Unknown! (255)
        Port: Twisted Pair
        PHYAD: 1
        Transceiver: internal
        Auto-negotiation: on
        Supports Wake-on: umbg
        Wake-on: d
        Current message level: 0x00000007 (7)
        Link detected: no


# mii-tool eth2
eth2: negotiated 100baseTx-FD flow-control, link ok




I think I should believe ethtool, but I see the LED lights green, the cables is properlly plugged (tried with two different ones).
Any idea why interefaces are down and can't communicate?


Last:

Here are the drivers:

Code:
# ethtool -i eth2
driver: e1000
version: 7.4.24b-NAPI
firmware-version: 5.12-2
bus-info: 0d:00.0

Thanks
Last edited by pludi; 05-07-2010 at 03:42 AM.. Reason: code tags, please...
# 2  
Old 05-07-2010
This:
Code:
UP BROADCAST MULTICAST  MTU:1500  Metric:1

...is odd. On my systems I have
Code:
UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1

It really doesn't believe the cable's plugged in. The LED's might just be hardwired. mii-tool talks with the transceiver itself, so it's the one I'd trust... Very strange that it autonegotiated a 100baseT link with a 1000baseT peer.

Have you tried a normal cable, not a crossover cable? I've sometimes experienced odd behavior with ports capable of autodetecting the cable type. You might also try forcing the speed and duplex, gigabit links often have problems negotiating -- though if you've discovered a gigabit interface that's incapable of negotiating with itself that's certainly something new! Smilie
# 3  
Old 05-08-2010
Corona688 is correct. Generally no need for a crossover cable for Gigabit NICs.

If you connect these systems into your network, can they communicate with each other?

I see you have other network adapters in your systems. Are they in use?

Are you using the exact same NICs (make, model#, driver) on both systems? NC373i?
Last edited by fpmurphy; 05-08-2010 at 11:57 AM..
# 4  
Old 05-08-2010
Quote:
Originally Posted by fpmurphy
I see you have other network adapters in your systems. Are they in use?
I wondered too. I assumed it's a two-port nic and wondered why eth2 and not eth0 or eth1. Besides I looked at the support pages @ hp.com, namely the driver download section and I found the driver the OP has mentioned (e1000), but there is a e1000e too. I don't know what's the difference between them. There are even at least two non-intel drivers (Broadcom, QLogic) Smilie
This User Gave Thanks to pseudocoder For This Post:
ravidborse
Login or Register to Ask a Question

Previous Thread | Next Thread

9 More Discussions You Might Find Interesting

1. AIX

How to check the ethernet status for vlan and lhea adapter in client servers?

Hi Techies, I have a doubt. ent0 Available Logical Host Ethernet Port (lp-hea) ent1 Available Logical Host Ethernet Port (lp-hea) ent2 Available Logical Host Ethernet Port (lp-hea) ent3 Available Logical Host Ethernet Port (lp-hea) ent4 Available... (4 Replies)
Discussion started by: jayadeava
4 Replies

2. AIX

vio server ethernet to vio client ethernet(concepts confusing)

Hi In the vio server when I do # lsattr -El hdisk*, I get a PVID. The same PVID is also seen when I put the lspv command on the vio client partition. This way Im able to confirm the lun using the PVID. Similarly how does the vio client partition gets the virtual ethernet scsi client adapter... (1 Reply)
Discussion started by: newtoaixos
1 Replies

3. Red Hat

Different hostnames with reboot while lan cable, no lan cable

I am facing strange problem regarding hostname on my Linux(2.6.18-164.el5xen x86_64 GNU/Linux), the hostname changes if reboot with lan cable and with NO lan cable Reboot with lan cable: The hostname is ubunut Unable to connect Oracle database using sqlplus some times database is not... (2 Replies)
Discussion started by: LinuxLearner
2 Replies

4. Programming

How detect TCP/IP socket shutdown when ethernet cable is disconnected

Hi, I want to code TCP/IP client/server in linux application capable to fastly detect ethernet cable disconnection in any condition. So I have activate SO_KEEPALIVE options and set TCP_KEEPCNT, TCP_KEEPIDLE and TCP_KEEPINTVL to 1. When I disconnect ethernet cable I have the following... (5 Replies)
Discussion started by: jeje_clb
5 Replies

5. UNIX for Dummies Questions & Answers

How to change ethernet cable of iscsi initiator (iscsi client)?

how to change ethernet cable of iscsi initiator (iscsi client) (0 Replies)
Discussion started by: pankajd
0 Replies

6. IP Networking

How to handle unplugging ethernet cable in socket programming

Hi, I am trying to implement a server-client socket communication. My server and clients are in different PCs. During communications if the ethernet cable is removed from the server side it shows broken pipe due to unable to write on the socket. I want to know how to check whether the ethernet... (0 Replies)
Discussion started by: JagadishB
0 Replies

7. Red Hat

[RHEL4.5] server shutdown when I unplug the ethernet cable

hi.. I unplug my eth0 lan cable.. and suddenly my system shutdown... no idea :eek::confused: (3 Replies)
Discussion started by: flekzout
3 Replies

8. High Performance Computing

Normal (not crossover) cable for Sun cluster interconnect..

Hi grus, has anybody tried for Sun cluster interconnect normal cable ,, I mean not interconnect .. What do u think ..does it support this ? Not long ago I tried Veritas cluster and its interconnections work great with normal cable .. I wonder what will Sun cluster say to it :)) (3 Replies)
Discussion started by: samar
3 Replies

9. Solaris

Is the cable you are using a null modem cable or a modem cable

Hi all, Is there any difference between a null modem cable or a modem cable ? i assume that a null modem cable is a normal cable that i used from cpu serial ports to a modem for dialup. please correct if i am wrong, thks (2 Replies)
Discussion started by: waterbear
2 Replies
Login or Register to Ask a Question