My network issues first started when I got a DNS error, so I started trying to change my DNS server to Cloudflare/Google DNS. I started reading how to do this and I found that latest Ubuntu releases use Netplan.
Configs for Netplan are stored in /etc/netplan/, but when I looked into this folder, I found that there was only one file and this file was called 00-install.yml or something like that. After searching and testing some things I found that my networking isn't using /etc/network/interfaces (this file was empty/non-existing), and I just started creating new Netplan config.
After a big amount of restarts and typing without screen, I got it to working. DNS still didn't work in most of applications, and googling again I found that I have to change /etc/resolv.conf symlink?????? It is strange, but I did this and now DNS in resolv.conf is equals to that in my Netplan config (/etc/netplan/01-cfg.yml), and all worked great.
Until I tried downloading LinuxGSM server. ./gmodserver install command starts with downloading some shell scripts one by one from Github (or Bitbucket on fail, uses CURL for both), and it started downloading, then some scripts failed to download and script failed. After re-running the command more than 20 times and rebooting, script was finally working.
From this moment network problems got worse. Ping and curl mostly stopped working. I found one answer that said to try telneting to Google and it worked, but slow. I tried to fix this issue: using DHCP/static ip, changing ip, changing nameservers, removing nameserver options, switched from Netplan to ifupdown (/etc/network/interfaces).
What I have currently:
Ubuntu 20.04.4 LTS x86_64, ifupdown networking, UFW disabled, Cloudflare DNS, Ping dropping packets randomly:
stopper@stopperls:~$ ping [Ubuntu Changelogs]
PING [Ubuntu Changelogs] 56(84) bytes of data.
64 bytes from amyrose.canonical.com: icmp_seq=1 ttl=53 time=168 ms
# ... worked another 12 times
^C
--- [Ubuntu Changelogs] ping statistics ---
19 packets transmitted, 13 received, 31.5789% packet loss, time 18131ms
rtt min/avg/max/mdev = 166.969/167.842/168.108/0.275 ms
# It's starting fine, but then stops working:
stopper@stopperls:~$ ping [Ubuntu Changelogs]
PING [Ubuntu Changelogs] 56(84) bytes of data.
^C
--- [Ubuntu Changelogs] ping statistics ---
2 packets transmitted, 0 received, 100% packet loss, time 1014ms
# Tried disabling IPv6 (already disabled in some sysctl file but this file is looks like ignored for some reason):
stopper@stopperls:~$ sudo sysctl -w net.ipv6.conf.all.disable_ipv6=1
[sudo] password for stopper:
net.ipv6.conf.all.disable_ipv6 = 1
stopper@stopperls:~$ sudo sysctl -w net.ipv6.conf.default.disable_ipv6=1
net.ipv6.conf.default.disable_ipv6 = 1
stopper@stopperls:~$ ping [Ubuntu Changelogs]
PING [Ubuntu Changelogs] (185.125.190.17) 56(84) bytes of data.
^C
--- [Ubuntu Changelogs] ping statistics ---
4 packets transmitted, 0 received, 100% packet loss, time 3052ms
# And it started working for a little bit again:
stopper@stopperls:~$ ping [Ubuntu Changelogs]
PING [Ubuntu Changelogs] 56(84) bytes of data.
# ... worked another 8 times
^C
--- [Ubuntu Changelogs] ping statistics ---
16 packets transmitted, 8 received, 50% packet loss, time 15162ms
rtt min/avg/max/mdev = 166.739/167.794/168.258/0.418 ms
On SSH connection, I get Failed to connect to [Ubuntu Changelogs]/meta-release-lts. Check your Internet connection or proxy settings
Curling [Google] is breaking some times:
stopper@stopperls:~$ curl [Google]
curl: (56) Recv failure: Connection reset by peer
stopper@stopperls:~$ curl [Google]
<HTML><HEAD><meta http-equiv="content-type" content="text/html;charset=utf-8">
<TITLE>301 Moved</TITLE></HEAD><BODY>
<H1>301 Moved</H1>
The document has moved
<A HREF="[Google]">here</A>.
</BODY></HTML>
# ... worked another 5 times
stopper@stopperls:~$ curl [Google]
# Was frozen for a minute+
curl: (7) Failed to connect to [Google] port 80: Connection timed out
stopper@stopperls:~$ curl [Google]
curl: (56) Recv failure: Connection reset by peer
enp4s0 is main interface - on-board Realtek RTL8111D
04:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller (rev 03)
Subsystem: Gigabyte Technology Co., Ltd Onboard Ethernet
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 31
Region 0: I/O ports at ee00 [size=256]
Region 2: Memory at fbcff000 (64-bit, prefetchable) [size=4K]
Region 4: Memory at fbcf8000 (64-bit, prefetchable) [size=16K]
Expansion ROM at fbd00000 [virtual] [disabled] [size=128K]
Capabilities: [40] Power Management version 3
Flags: PMEClk- DSI- D1+ D2+ AuxCurrent=375mA PME(D0+,D1+,D2+,D3hot+,D3cold+)
Status: D0 NoSoftRst+ PME-Enable- DSel=0 DScale=0 PME-
Capabilities: [50] MSI: Enable+ Count=1/1 Maskable- 64bit+
Address: 00000000fee08004 Data: 4024
Capabilities: [70] Express (v2) Endpoint, MSI 01
DevCap: MaxPayload 256 bytes, PhantFunc 0, Latency L0s <512ns, L1 <64us
ExtTag- AttnBtn- AttnInd- PwrInd- RBE+ FLReset- SlotPowerLimit 10.000W
DevCtl: CorrErr- NonFatalErr- FatalErr- UnsupReq-
RlxdOrd+ ExtTag- PhantFunc- AuxPwr- NoSnoop-
MaxPayload 128 bytes, MaxReadReq 4096 bytes
DevSta: CorrErr- NonFatalErr- FatalErr- UnsupReq- AuxPwr+ TransPend-
LnkCap: Port #0, Speed 2.5GT/s, Width x1, ASPM L0s L1, Exit Latency L0s <512ns, L1 <64us
ClockPM+ Surprise- LLActRep- BwNot- ASPMOptComp-
LnkCtl: ASPM Disabled; RCB 64 bytes Disabled- CommClk+
ExtSynch- ClockPM- AutWidDis- BWInt- AutBWInt-
LnkSta: Speed 2.5GT/s (ok), Width x1 (ok)
TrErr- Train- SlotClk+ DLActive- BWMgmt- ABWMgmt-
DevCap2: Completion Timeout: Not Supported, TimeoutDis+, NROPrPrP-, LTR-
10BitTagComp-, 10BitTagReq-, OBFF Not Supported, ExtFmt-, EETLPPrefix-
EmergencyPowerReduction Not Supported, EmergencyPowerReductionInit-
FRS-, TPHComp-, ExtTPHComp-
AtomicOpsCap: 32bit- 64bit- 128bitCAS-
DevCtl2: Completion Timeout: 50us to 50ms, TimeoutDis-, LTR-, OBFF Disabled
AtomicOpsCtl: ReqEn-
LnkCtl2: Target Link Speed: 2.5GT/s, EnterCompliance- SpeedDis-
Transmit Margin: Normal Operating Range, EnterModifiedCompliance- ComplianceSOS-
Compliance De-emphasis: -6dB
LnkSta2: Current De-emphasis Level: -6dB, EqualizationComplete-, EqualizationPhase1-
EqualizationPhase2-, EqualizationPhase3-, LinkEqualizationRequest-
Capabilities: [ac] MSI-X: Enable- Count=4 Masked-
Vector table: BAR=4 offset=00000000
PBA: BAR=4 offset=00000800
Capabilities: [cc] Vital Product Data
pcilib: sysfs_read_vpd: read failed: Input/output error
Not readable
Capabilities: [100 v1] Advanced Error Reporting
UESta: DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt- UnxCmplt- RxOF- MalfTLP- ECRC- UnsupReq- ACSViol-
UEMsk: DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt- UnxCmplt- RxOF- MalfTLP- ECRC- UnsupReq+ ACSViol-
UESvrt: DLP+ SDES+ TLP- FCP+ CmpltTO- CmpltAbrt- UnxCmplt- RxOF+ MalfTLP+ ECRC- UnsupReq- ACSViol-
CESta: RxErr- BadTLP- BadDLLP- Rollover- Timeout- AdvNonFatalErr-
CEMsk: RxErr- BadTLP- BadDLLP- Rollover- Timeout- AdvNonFatalErr+
AERCap: First Error Pointer: 00, ECRCGenCap+ ECRCGenEn- ECRCChkCap+ ECRCChkEn-
MultHdrRecCap- MultHdrRecEn- TLPPfxPres- HdrLogCap-
HeaderLog: 00000000 00000000 00000000 00000000
Capabilities: [140 v1] Virtual Channel
Caps: LPEVC=0 RefClk=100ns PATEntryBits=1
Arb: Fixed- WRR32- WRR64- WRR128-
Ctrl: ArbSelect=Fixed
Status: InProgress-
VC0: Caps: PATOffset=00 MaxTimeSlots=1 RejSnoopTrans-
Arb: Fixed- WRR32- WRR64- WRR128- TWRR128- WRR256-
Ctrl: Enable+ ID=0 ArbSelect=Fixed TC/VC=ff
Status: NegoPending- InProgress-
Capabilities: [160 v1] Device Serial Number 03-00-00-00-68-4c-e0-00
Kernel driver in use: r8168
Kernel modules: r8168
route -n:
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
0.0.0.0 192.168.32.1 0.0.0.0 UG 0 0 0 enp4s0
172.17.0.0 0.0.0.0 255.255.0.0 U 0 0 0 docker0
172.18.0.0 0.0.0.0 255.255.0.0 U 0 0 0 br-44b6209c823e
172.19.0.0 0.0.0.0 255.255.0.0 U 0 0 0 br-ec985c658a3b
172.20.0.0 0.0.0.0 255.255.0.0 U 0 0 0 br-50806f0cc08b
172.21.0.0 0.0.0.0 255.255.0.0 U 0 0 0 br-8d4bdd62462b
192.168.32.0 0.0.0.0 255.255.255.0 U 0 0 0 enp4s0
192.168.32.0 0.0.0.0 255.255.255.0 U 0 0 0 br-c709a7686d7e
ifconfig:
br-44b6209c823e: flags=4099<UP,BROADCAST,MULTICAST> mtu 1500
inet 172.18.0.1 netmask 255.255.0.0 broadcast 172.18.255.255
ether 02:42:3c:4f:7a:1a txqueuelen 0 (Ethernet)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 0 bytes 0 (0.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
br-50806f0cc08b: flags=4099<UP,BROADCAST,MULTICAST> mtu 1500
inet 172.20.0.1 netmask 255.255.0.0 broadcast 172.20.255.255
ether 02:42:5b:90:b1:1a txqueuelen 0 (Ethernet)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 0 bytes 0 (0.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
br-8d4bdd62462b: flags=4099<UP,BROADCAST,MULTICAST> mtu 1500
inet 172.21.0.1 netmask 255.255.0.0 broadcast 172.21.255.255
ether 02:42:ff:b3:27:4c txqueuelen 0 (Ethernet)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 0 bytes 0 (0.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
br-c709a7686d7e: flags=4099<UP,BROADCAST,MULTICAST> mtu 1500
inet 192.168.32.1 netmask 255.255.255.0 broadcast 192.168.32.255
ether 02:42:bb:26:20:58 txqueuelen 0 (Ethernet)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 0 bytes 0 (0.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
br-ec985c658a3b: flags=4099<UP,BROADCAST,MULTICAST> mtu 1500
inet 172.19.0.1 netmask 255.255.0.0 broadcast 172.19.255.255
ether 02:42:90:ae:ea:6b txqueuelen 0 (Ethernet)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 0 bytes 0 (0.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
docker0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 172.17.0.1 netmask 255.255.0.0 broadcast 172.17.255.255
ether 02:42:e7:47:61:e2 txqueuelen 0 (Ethernet)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 53 bytes 8827 (8.8 KB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
enp4s0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.32.108 netmask 255.255.255.0 broadcast 192.168.32.255
ether 1c:6f:65:21:0c:cb txqueuelen 1000 (Ethernet)
RX packets 354430 bytes 21343825 (21.3 MB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 2036 bytes 137535 (137.5 KB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 # note that 0 dropped
device interrupt 31 base 0xd000
lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
inet 127.0.0.1 netmask 255.0.0.0
loop txqueuelen 1000 (Local Loopback)
RX packets 86 bytes 6220 (6.2 KB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 86 bytes 6220 (6.2 KB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
veth050959f: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
ether 5e:ea:3a:8b:e8:61 txqueuelen 0 (Ethernet)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 53 bytes 8827 (8.8 KB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
ip a:
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
2: enp4s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
link/ether 1c:6f:65:21:0c:cb brd ff:ff:ff:ff:ff:ff
inet 192.168.32.108/24 brd 192.168.32.255 scope global enp4s0
valid_lft forever preferred_lft forever
3: br-50806f0cc08b: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default
link/ether 02:42:5b:90:b1:1a brd ff:ff:ff:ff:ff:ff
inet 172.20.0.1/16 brd 172.20.255.255 scope global br-50806f0cc08b
valid_lft forever preferred_lft forever
4: br-8d4bdd62462b: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default
link/ether 02:42:ff:b3:27:4c brd ff:ff:ff:ff:ff:ff
inet 172.21.0.1/16 brd 172.21.255.255 scope global br-8d4bdd62462b
valid_lft forever preferred_lft forever
5: docker0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default
link/ether 02:42:e7:47:61:e2 brd ff:ff:ff:ff:ff:ff
inet 172.17.0.1/16 brd 172.17.255.255 scope global docker0
valid_lft forever preferred_lft forever
6: br-c709a7686d7e: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default
link/ether 02:42:bb:26:20:58 brd ff:ff:ff:ff:ff:ff
inet 192.168.32.1/24 brd 192.168.32.255 scope global br-c709a7686d7e
valid_lft forever preferred_lft forever
7: br-ec985c658a3b: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default
link/ether 02:42:90:ae:ea:6b brd ff:ff:ff:ff:ff:ff
inet 172.19.0.1/16 brd 172.19.255.255 scope global br-ec985c658a3b
valid_lft forever preferred_lft forever
8: br-44b6209c823e: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default
link/ether 02:42:3c:4f:7a:1a brd ff:ff:ff:ff:ff:ff
inet 172.18.0.1/16 brd 172.18.255.255 scope global br-44b6209c823e
valid_lft forever preferred_lft forever
10: veth050959f@if9: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master docker0 state UP group default
link/ether 5e:ea:3a:8b:e8:61 brd ff:ff:ff:ff:ff:ff link-netnsid 0
cat /etc/network/interfaces:
stopper@stopperls:~$ cat /etc/network/interfaces
# interfaces(5) file used by ifup(8) and ifdown(8)
# Include files from /etc/network/interfaces.d:
source-directory /etc/network/interfaces.d
# The loopback network interface
auto lo
iface lo inet loopback
allow-hotplug enp4s0
auto enp4s0
iface enp4s0 inet static
address 192.168.32.108
netmask 255.255.255.0
broadcast 192.168.32.255
gateway 192.168.32.1
dns-nameservers 1.1.1.1 1.0.0.1
Also no proxy:
stopper@stopperls:~$ echo "$http_proxy"
stopper@stopperls:~$ echo "$https_proxy"
stopper@stopperls:~$ echo "$all_proxy"
stopper@stopperls:~$
On Manjaro machine CURL works perfectly, PING too (and just generally I doesn't have any network issues on my Manjaro PC, DNS server is Auto (so probably not Cloudflare/Google DNS, and probably this is that DNS what had problems on Ubuntu Server))
