Настройка работы сервера на CentOS с 2 шлюзами и балансировки между ними

[root@serv network-scripts]# cat ifup-post
#!/bin/sh

cd /etc/sysconfig/network-scripts
. ./network-functions

[ -f ../network ] && . ../network

unset REALDEVICE
if [ "$1" = --realdevice ] ; then
    REALDEVICE=$2
    shift 2
fi

CONFIG=$1
source_config

[ -z "$REALDEVICE" ] && REALDEVICE=$DEVICE

if [ "$ISALIAS" = no ] ; then
    /etc/sysconfig/network-scripts/ifup-aliases ${DEVICE} ${CONFIG}
fi

/etc/sysconfig/network-scripts/ifup-routes ${REALDEVICE} ${DEVNAME}


if [ "$PEERDNS" != "no" -o -n "$RESOLV_MODS" -a "$RESOLV_MODS" != "no" ]; then
  [ -n "$MS_DNS1" ] && DNS1=$MS_DNS1
  [ -n "$MS_DNS2" ] && DNS2=$MS_DNS2
  if [ -n "$DNS1" ] && ! grep -q "^nameserver $DNS1" /etc/resolv.conf &&
   tr=`mktemp /tmp/XXXXXX` ; then
    current_replacement="$DNS1"
    next_replacement="$DNS2"
    search=
    (cat /etc/resolv.conf ; echo EOF ; echo EOF) | while read answer ; do
        case $answer in
            nameserver*|EOF)
                if [ -n "$current_replacement" ] ; then
                    echo "nameserver $current_replacement" >> $tr
                    if [ -n "$next_replacement" ] ; then
                        current_replacement="$next_replacement"
                        next_replacement=
                    else
                        current_replacement=
                    fi
                else
                    if [ "$answer" != EOF ] ; then
                        echo "$answer" >> $tr
                    fi
                fi
                ;;
            domain*|search*)
                if [ -n "$DOMAIN" ]; then
                    echo "$answer" | while read key value ; do
                        search="$search $value"
                    done
                else
                    echo "$answer" >> $tr
                fi
                ;;
            *)
                echo "$answer" >> $tr
                ;;
        esac
    done
    if [ -n "$DOMAIN" ]; then
        echo "search $DOMAIN $search" >> $tr
    fi

    # backup resolv.conf
    cp -af /etc/resolv.conf /etc/resolv.conf.save

    # maintain permissions
    # but set umask in case it doesn't exist!
    oldumask=`umask`
    umask 022
    change_resolv_conf $tr
    rm -f $tr
    umask $oldumask
  fi
fi

# don't set hostname on ppp/slip connections
if [ "$2" = "boot" -a \
     "${DEVICE}" != lo -a \
     "${DEVICETYPE}" != "ppp" -a \
     "${DEVICETYPE}" != "slip" ]; then
    if need_hostname; then
        IPADDR=`LANG= LC_ALL= ifconfig ${DEVICE} | grep 'inet addr' |
                awk -F: '{ print $2 } ' | awk '{ print $1 }'`
        eval `/bin/ipcalc --silent --hostname ${IPADDR}`
        if [ "$?" = "0" ]; then
            set_hostname $HOSTNAME
        fi
    fi
fi

# Notify programs that have requested notification
do_netreport

if [ -x /sbin/ifup-local ]; then
    /sbin/ifup-local ${DEVICE}
fi

exit 0