Hello,
I selected your operating system and I have a problem. There are two network cards installed in my PC. From lspci I see them:
02:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller (rev 02)
03:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller (rev 0c)
But I only see one in my system. I have latest OpenSuse Leap. Any idea how to solve my problem?
Hello and welcome to the openSUSE forums.
You say “I only see one in my system.”, but you fail to explain how you see that. In fact you show with your lspci output (next time , please also include the line with the command withing the CODE section, so we can see what you did) that the system detected two,
OK. I have 2 network cards in my computer. The first is integrated and the second is added to the PCI slot. But I only see an integrated card in the system. And I don’t know how to activate the second adapter. All I know is the lspci command. : '( Can you help with the second adapter?
test@localhost:~> sudo lspci[sudo] heslo pro root:
00:00.0 Host bridge: Intel Corporation 4th Gen Core Processor DRAM Controller (rev 06)
00:02.0 VGA compatible controller: Intel Corporation Xeon E3-1200 v3/4th Gen Core Processor Integrated Graphics Controller (rev 06)
00:03.0 Audio device: Intel Corporation Xeon E3-1200 v3/4th Gen Core Processor HD Audio Controller (rev 06)
00:14.0 USB controller: Intel Corporation 8 Series/C220 Series Chipset Family USB xHCI (rev 04)
00:16.0 Communication controller: Intel Corporation 8 Series/C220 Series Chipset Family MEI Controller #1 (rev 04)
00:1a.0 USB controller: Intel Corporation 8 Series/C220 Series Chipset Family USB EHCI #2 (rev 04)
00:1b.0 Audio device: Intel Corporation 8 Series/C220 Series Chipset High Definition Audio Controller (rev 04)
00:1c.0 PCI bridge: Intel Corporation 8 Series/C220 Series Chipset Family PCI Express Root Port #1 (rev d4)
00:1c.2 PCI bridge: Intel Corporation 8 Series/C220 Series Chipset Family PCI Express Root Port #3 (rev d4)
00:1c.3 PCI bridge: Intel Corporation 8 Series/C220 Series Chipset Family PCI Express Root Port #4 (rev d4)
00:1d.0 USB controller: Intel Corporation 8 Series/C220 Series Chipset Family USB EHCI #1 (rev 04)
00:1f.0 ISA bridge: Intel Corporation H81 Express LPC Controller (rev 04)
00:1f.2 SATA controller: Intel Corporation 8 Series/C220 Series Chipset Family 6-port SATA Controller 1 [AHCI mode] (rev 04)
00:1f.3 SMBus: Intel Corporation 8 Series/C220 Series Chipset Family SMBus Controller (rev 04)
02:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller (rev ff)
03:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller (rev 0c)
test@localhost:~>
Aagain. where/how do you “see” this?
The only thing we "see: is that the system detected two cards, one at 02:00.0 and one at 03:00.0.
Where are you looking and not seeing one of them.
Do not assume we are mind readers. Do not assume we do all the time the same thing that you are doing. There are many ways/tools/programs to look at ethernet cards and report about them
Maybe you can post (as root):
ip addr
Install package yast2-tune.
Look in Yast -> Hardware Information. What are the drivers of the cards?
Can you confirm that a card is installed in PCI slot and not PCIe?
I’m fixing this problem with another ethernet card.
I received an Intel Ethernet card from another Windows computer and replaced the problem card in the Linux computer with this card. Now the Inten card works well.
Nice you solved it. But we still do not know what you did. Well, forget it. 
It is easy. I have two internet networks.
The 1st network is the Internet for a remote desktop workstation.
The 2nd network is an isolated network.
But only one card worked properly. And I need two Ethernet cards in my computer. But only one card (internal on the motherboard) worked properly and the Realtek card worked very badly. So I replaced the Realtek card with an Intel card and everything works very well now.
This is all talking after you solved it already, but it might be important when you have another problem in the future.
You only tell here what you think that happens, like “worked very badly” and “I do not see the card”, but you failed complete in telling us how you came to those conclusions. We have not very much more then the infamous “it does not work”.
Always show us with commands and their output (next best is screen copies posted in https://susepaste.org/ ) what you did and what you got.
And maybe read a bit in How To Ask Questions The Smart Way . It is not all applicable to the forums here (and people are mostly very kind), but much is.