I had my connection drop intermittently with an r8168 based NIC (about 1 minute dropout every 1 minute).
It seemed as thought my problem was having the r8169 kernel module loaded as others have experienced.
I followed the instructions in this blog post, and installed the 8.035.00 drivers found on this page.
It looks like I have the r8168 module loading, however the network dropouts still occur.
This is an issue as I'm trying to set this machine up as a webserver.
dmesg | grep r8:
[ 0.000000] PERCPU: Embedded 28 pages/cpu @ffff88021f200000 s83584 r8192 d22912 u524288
[ 0.000000] pcpu-alloc: s83584 r8192 d22912 u524288 alloc=1*2097152
[ 0.859374] r8168 Gigabit Ethernet driver 8.031.00-NAPI loaded
[ 0.859478] r8168 0000:04:00.0: irq 45 for MSI/MSI-X
[ 1.023716] r8168: This product is covered by one or more of the following patents: US5,307,459, US5,434,872, US5,732,094, US6,570,884, US6,115,776, and US6,327,625.
[ 1.023719] r8168 Copyright (C) 2012 Realtek NIC software team <firstname.lastname@example.org>
[ 8.845298] r8168: eth1: link down
[ 11.575182] r8168: eth1: link up
[ 11.844758] r8168: eth1: link up
04:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168B PCI Express Gigabit Ethernet controller (rev 06)
Subsystem: ASRock Incorporation Motherboard (one of many)
Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx+
Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
Latency: 0, Cache Line Size: 64 bytes
Interrupt: pin A routed to IRQ 45
Region 0: I/O ports at d000 [size=256]
Region 2: Memory at f0004000 (64-bit, prefetchable) [size=4K]
Region 4: Memory at f0000000 (64-bit, prefetchable) [size=16K]
Capabilities: <access denied>
Kernel driver in use: r8168
Kernel modules: r8168, r8169
64 bytes from iad23s05-in-f5.1e100.net (18.104.22.168): icmp_req=24 ttl=57 time=6.30 ms
64 bytes from iad23s05-in-f5.1e100.net (22.214.171.124): icmp_req=25 ttl=57 time=6.25 ms
64 bytes from iad23s05-in-f5.1e100.net (126.96.36.199): icmp_req=26 ttl=57 time=6.18 ms
64 bytes from iad23s05-in-f5.1e100.net (188.8.131.52): icmp_req=27 ttl=57 time=6.26 ms
64 bytes from iad23s05-in-f5.1e100.net (184.108.40.206): icmp_req=28 ttl=57 time=6.24 ms
64 bytes from iad23s05-in-f5.1e100.net (220.127.116.11): icmp_req=29 ttl=57 time=6.25 ms
--- google.com ping statistics ---
55 packets transmitted, 29 received, 47% packet loss, time 54043ms
rtt min/avg/max/mdev = 6.182/6.242/6.302/0.061 ms