De uma olhada no arquivo abaixo
/etc/udev/rules.d# less z25_persistent-net.rules
neste arquivo ficam as config de nomes das eths, se necessario edite alguma eth, alterando de eth0 para eth2 por exemplo e salve o arquivo, após isso se vc retirar alguma placa de rede ele nao mais suibstituirá e sim incrementará no numero de eths.
Após salvar o arquivo reboot a maquina varias vezes e veja que nao mais mudará o nome das eths.
o arquivo é igual ao abaixo.
# This file was automatically generated by the /lib/udev/write_net_rules
# program, probably run by the persistent-net-generator.rules rules file.
#
# You can modify it, as long as you keep each rule on a single line.
# MAC addresses must be written in lowercase.
# PCI device 0x10b7:0x9200 (3c59x)
SUBSYSTEM=="net", DRIVERS=="?*", ATTRS{address}=="99:99:99:99:99:99", NAME="eth3"
# PCI device 0x10b7:0x9200 (3c59x)
SUBSYSTEM=="net", DRIVERS=="?*", ATTRS{address}=="99:99:99:99:99:88", NAME="eth4"
# PCI device 0x8086:0x27dc (e100)
SUBSYSTEM=="net", DRIVERS=="?*", ATTRS{address}=="99:99:99:99:99:77", NAME="eth0"
# PCI device 0x10b7:0x9055 (3c59x)
SUBSYSTEM=="net", DRIVERS=="?*", ATTRS{address}=="99:99:99:99:99:66", NAME="eth1"
# PCI device 0x10b7:0x9055 (3c59x)
SUBSYSTEM=="net", DRIVERS=="?*", ATTRS{address}=="99:99:99:99:99:55", NAME="eth2"
Valeu.