uBuntu 10.10 is not being friendly

Hi guys.
I have a very peculiar problem that coffee and effort just cannot seem to fix
I have a web server sitting at a data centre with a direct line into the internet(bad practise i know, i got told off by a pro but its too late now).

Im running uBuntu 10.10 server edition on a ASUS r300 rackmount server 4 gb ram 2 ethernet cards and a XEON processor ... standard stuff i would assume.

My problem is that my internet connection is highly unstable, and whats worse is that a simple /etc/init.d/networking restart does not do the trick.

the basic jist of the past 48 hrs involves me trying different configurations, then trying the restart script... then wondering why it does not work ... then rebooting (yes i just came from windows).

When it reboots it works for about 2 minutes (the internet) then it dies, i then try /etc/init.d/networking restart to no effect followed by a reboot which works.

i have ifconfig, /network/interfaces and init.d/networking

Code:

-------------ifconfig:-------------------

eth0      Link encap:Ethernet  HWaddr e0:cb:4e:12:78:35  
          inet addr:125.7.41.XXX  Bcast:125.7.41.XXX  Mask:255.255.255.240
          inet6 addr: fe80::e2cb:4eff:fe12:7835/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:48 errors:0 dropped:0 overruns:0 frame:0
          TX packets:67 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:5210 (5.2 KB)  TX bytes:6802 (6.8 KB)
          Interrupt:18 Memory:fbce0000-fbd00000 

lo        Link encap:Local Loopback  
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:11 errors:0 dropped:0 overruns:0 frame:0
          TX packets:11 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:1124 (1.1 KB)  TX bytes:1124 (1.1 KB)
		  
---------network/interfaces--------------
/*------------------------------------

as you can see here i have two network cards with different public ips
but for debugging purposes i have disabled the second one 
(this text is not in the file)

-------------------------------------*/

# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).

# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
auto eth0
iface eth0 inet static
	address 125.7.41.XXX
	netmask 255.255.255.240
	network 125.7.41.XXX
	broadcast 125.7.41.XXX
	gateway 125.7.41.XXX
	# dns-* options are implemented by the resolvconf package, if installed
	#dns-nameservers 203.110.136.142 203.110.136.131
	#dns-search doesnotmatter.com

#auto eth1
#iface eth1 inet static
#	address 125.7.41.XXX
#	netmask 255.255.255.240
#	network 125.7.41.XXX
#	broadcast 125.7.41.XXX
#	gateway 125.7.41.XXX
	# dns-* options are implemented by the resolvconf package, if installed
	#dns-nameservers 203.110.136.142 203.110.136.131
	#dns-search doesnotmatter.com
	
-------------------/etc/init.d/networking--------------------


#!/bin/sh -e
### BEGIN INIT INFO
# Provides:          networking
# Required-Start:
# Required-Stop:     $local_fs
# Default-Start:
# Default-Stop:      0 6
# Short-Description: Raise network interfaces.
### END INIT INFO

PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin"

[ -x /sbin/ifup ] || exit 0

. /lib/lsb/init-functions

# helper function to set the usplash timeout. https://launchpad.net/bugs/21617
usplash_timeout () {
        TIMEOUT=$1
        if [ -x /sbin/usplash_write ]; then
            /sbin/usplash_write "TIMEOUT $TIMEOUT" || true
        fi
}

process_options() {
    [ -e /etc/network/options ] || return 0
    log_warning_msg "/etc/network/options still exists and it will be IGNORED! Read README.Debian of netbase."
}

check_network_file_systems() {
    [ -e /proc/mounts ] || return 0

    if [ -e /etc/iscsi/iscsi.initramfs ]; then
        # probably root on iSCSI
        log_warning_msg "not deconfiguring network interfaces: root filesystem appears to be on iSCSI."
        exit 0
    fi

    exec 9<&0 < /proc/mounts
    while read DEV MTPT FSTYPE REST; do
        case $DEV in
        /dev/nbd*|/dev/nd[a-z]*|/dev/etherd/e*)
            log_warning_msg "not deconfiguring network interfaces: network devices still mounted."
            exit 0
            ;;
        esac
        case $FSTYPE in
        nfs|nfs4|smbfs|ncp|ncpfs|cifs|coda|ocfs2|gfs|pvfs|pvfs2|fuse.httpfs|fuse.curlftpfs)
            log_warning_msg "not deconfiguring network interfaces: network file systems still mounted."
            exit 0
            ;;
        esac
    done
    exec 0<&9 9<&-
}

case "$1" in
start)
        /lib/init/upstart-job networking start
		

I've never seen this kind of thing before in my 6 months of linux fun, but then again I've never worked with a public IP before

 

OK advance on the problem.
It only happens when both ethernet cards are configured

ie eth1 is not commented out

This problem happens regardless of whether ufw is enabled or disabled

 

Problem solved.
When configuring multiple ethernet cards,
you can only have one gateway in interfaces:

Code:

auto eth0 eth1
iface eth0 inet static
	address 125.7.41.138
	netmask 255.255.255.240
	network 125.7.41.128
	broadcast 125.7.41.14
	gateway 125.7.41.142
iface eth1 inet static
	address 125.7.41.139
	netmask 255.255.255.240
	network 125.7.41.128

hopefully this saves someone a week

 

I had that same issue when I was first using linux. The way found the problem was running top and seeing the memory goto null from the network loop.