In my Ubuntu server 16.04 I have this file: /etc/network/interfaces
# The primary network interface
auto eth0
iface eth0 inet dhcp
#auto eth1
#iface eth1 inet static
# address 10.0.0.41
# netmask 255.255.255.0
# network 10.0.0.0
# broadcast 10.0.0.255
# gateway 10.0.0.1
The eth0 is linked to dsl, if I uncomment the eth1 section to enable second NIC card, I can't ping remote server like yahoo.com:
ping yahoo.com
PING yahoo.com (98.138.253.109) 56(84) bytes of data.
From 10.0.0.41 icmp_seq=1 Destination Host Unreachable
From 10.0.0.41 icmp_seq=2 Destination Host Unreachable
From 10.0.0.41 icmp_seq=3 Destination Host Unreachable
found a solution: remove the gateway 10.0.0.1
Related
This is route print output:
IPv4 Route Table
===========================================================================
Active Routes:
Network Destination Netmask Gateway Interface Metric
0.0.0.0 0.0.0.0 192.168.1.1 192.168.1.50 55
0.0.0.0 128.0.0.0 192.168.10.252 192.168.10.96 257
128.0.0.0 128.0.0.0 192.168.10.252 192.168.10.96 257
1.1.1.1 255.255.255.0 192.168.1.1 192.168.1.50 56
185.1.1.1.1 255.255.255.255 192.168.1.1 192.168.1.50 311
192.168.10.0 255.255.255.0 On-link 192.168.10.96 257
192.168.10.96 255.255.255.255 On-link 192.168.10.96 257
192.168.10.255 255.255.255.255 On-link 192.168.10.96 257
===========================================================================
Persistent Routes:
Network Address Netmask Gateway Address Metric
1.1.1.1 255.255.255.0 192.168.1.1 1
===========================================================================
As you see, 1.1.1.1/24 is added in routing table.
I want to delete a subnet (like /32 or bigger) from this but I get error:
route delete -p 1.1.1.10/32 192.168.1.1
route delete -p 1.1.1.0/25 192.168.1.1
Error:
The route deletion failed: Element not found.
I know I can remove the whole /24 subnet and then use a Python script to generate the desired subnets, but my question is whether it's possible to remove a smaller subnet in routing table.
Windows 10, PowerShell version is 5.1 (18200).
Running a clean install of microk8s 1.19 on Fedora 32, I am able to ping an external IP address, but when I try to wget, I get "no route to host" (this is the output of commands run from a busybox pod):
/ # wget x.x.x.x
Connecting to x.x.x.x (x.x.x.x:80)
wget: can't connect to remote host (x.x.x.x): No route to host
/ # ping x.x.x.x
PING x.x.x.x (x.x.x.x): 56 data bytes
64 bytes from x.x.x.x: seq=0 ttl=127 time=1.209 ms
64 bytes from x.x.x.x: seq=1 ttl=127 time=0.765 ms
Finally found https://github.com/ubuntu/microk8s/issues/408
Had to enable masquerade in the firewall zone associated with the bridge interface, or in my case, my ethernet connection.
I have installed Kubernetes cluster(one Master and one Worker- Node) on CentOS-8 OS stand-alone server separately as per the below link instructions.
https://www.tecmint.com/install-a-kubernetes-cluster-on-centos-8/
Weave-Net - CNI plugin installed as per above link. Now I can see below new network adapter in our K8s Master & Worker-Node server.
weave: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1376
inet 10.32.0.1 netmask 255.240.0.0 broadcast 10.47.255.255
inet6 fe80::a07d:21ff:fef1:4656 prefixlen 64 scopeid 0x20<link>
ether a2:7d:21:f1:46:56 txqueuelen 1000 (Ethernet)
RX packets 141 bytes 13322 (13.0 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 48 bytes 4896 (4.7 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
But the problem is from host server unable to ping (Or) access any of our remote site/location IPs (ping response given below). whereas Local IPs are pinging & accessible.
ping -c 4 120.121.5.48
PING 120.121.5.48 (120.121.5.48) 56(84) bytes of data.
From 10.32.0.1 icmp_seq=1 Destination Host Unreachable
From 10.32.0.1 icmp_seq=2 Destination Host Unreachable
From 10.32.0.1 icmp_seq=3 Destination Host Unreachable
From 10.32.0.1 icmp_seq=4 Destination Host Unreachable
--- 120.121.5.48 ping statistics ---
4 packets transmitted, 0 received, +4 errors, 100% packet loss, time 2999ms
pipe 4
Also from host server tried to connect our remote LDAP server through telnet it shows below error message.
# telnet 120.121.5.48 389
Trying 120.121.5.48...
telnet: connect to address 120.121.5.48: No route to host
In our K8s Master & Worker-Node server have 23 network adapters, Statically network IP have configured, So any additional configuration need to be configured for K8s CNI reachable in default routing?
ip route show & route -n output as follows.
# ip route show
default via 45.46.47.1 dev ens1f0 proto static metric 100
10.32.0.0/12 dev weave proto kernel scope link src 10.32.0.1
45.46.47.0/24 dev ens1f0 proto kernel scope link src 45.46.47.48 metric 100
172.17.0.0/16 dev docker0 proto kernel scope link src 172.17.0.1
192.168.122.0/24 dev virbr0 proto kernel scope link src 192.168.122.1 linkdown
# route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
0.0.0.0 45.46.47.1 0.0.0.0 UG 100 0 0 ens1f0
10.32.0.0 0.0.0.0 255.255.255.0 U 10 0 0 ens1f0
10.32.0.0 0.0.0.0 255.240.0.0 U 0 0 0 weave
45.46.47.0 0.0.0.0 255.255.255.0 U 100 0 0 ens1f0
172.17.0.0 0.0.0.0 255.255.0.0 U 0 0 0 docker0
192.168.122.0 0.0.0.0 255.255.255.0 U 0 0 0 virbr0
Tried to change the weave route to default with below command. it executed successfully, But still same problem.
ip route add 10.32.0.0/24 via 45.46.47.1 dev ens1f0 metric 100
Suppose if i run ifconfig weave down everything is working fine. But to use Kubernetes cluster i need Weave-net network adapter. So please help me to add IP route(s) So that my Kubernetes cluster addresses go via through appropriate adapter, So that i will be able to access both our local & remote location server.
I have changed the CNI-Weave-Net plugin to Flannel, now it is working as excepted.
I'm seeing a weird issue on kubernetes and I'm not sure how to debug it. The k8s environment was installed by kube-up for vsphere using the 2016-01-08 kube.vmdk
The symptom is that the dns for a container in a pod is not working correctly. When I logon to the kube-dns service to check the settings everything looks correct. When I ping outside the local network it works as it should but when I ping inside my local network it cannot reach any of the hosts.
For the following my host network is 10.1.1.x, the gateway / dns server is 10.1.1.1.
inside the kube-dns container:
(I can ping outside the network by ip and I can ping the gateway just fine. dns isn't working since the nameserver is unreachable)
kube#kubernetes-master:~$ kubectl --namespace=kube-system exec -ti kube-dns-v20-in2me -- /bin/sh
/ # cat /etc/resolv.conf
nameserver 10.1.1.1
options ndots:5
/ # ping google.com
^C
/ # ping 8.8.8.8
PING 8.8.8.8 (8.8.8.8): 56 data bytes
64 bytes from 8.8.8.8: seq=0 ttl=54 time=13.542 ms
64 bytes from 8.8.8.8: seq=1 ttl=54 time=13.862 ms
^C
--- 8.8.8.8 ping statistics ---
2 packets transmitted, 2 packets received, 0% packet loss
round-trip min/avg/max = 13.542/13.702/13.862 ms
/ # ping 10.1.1.1
PING 10.1.1.1 (10.1.1.1): 56 data bytes
^C
--- 10.1.1.1 ping statistics ---
4 packets transmitted, 0 packets received, 100% packet loss
/ # netstat -r
Kernel IP routing table
Destination Gateway Genmask Flags MSS Window irtt Iface
default 10.244.2.1 0.0.0.0 UG 0 0 0 eth0
10.244.2.0 * 255.255.255.0 U 0 0 0 eth0
/ # ping 10.244.2.1
PING 10.244.2.1 (10.244.2.1): 56 data bytes
64 bytes from 10.244.2.1: seq=0 ttl=64 time=0.249 ms
64 bytes from 10.244.2.1: seq=1 ttl=64 time=0.091 ms
^C
--- 10.244.2.1 ping statistics ---
2 packets transmitted, 2 packets received, 0% packet loss
round-trip min/avg/max = 0.091/0.170/0.249 ms
on the master:
kube#kubernetes-master:~$ netstat -r
Kernel IP routing table
Destination Gateway Genmask Flags MSS Window irtt Iface
default 10.1.1.1 0.0.0.0 UG 0 0 0 eth0
10.1.1.0 * 255.255.255.0 U 0 0 0 eth0
10.244.0.0 kubernetes-mini 255.255.255.0 UG 0 0 0 eth0
10.244.1.0 kubernetes-mini 255.255.255.0 UG 0 0 0 eth0
10.244.2.0 kubernetes-mini 255.255.255.0 UG 0 0 0 eth0
10.244.3.0 kubernetes-mini 255.255.255.0 UG 0 0 0 eth0
10.246.0.0 * 255.255.255.0 U 0 0 0 cbr0
172.17.0.0 * 255.255.0.0 U 0 0 0 docker0
kube#kubernetes-master:~$ ping 10.1.1.1
PING 10.1.1.1 (10.1.1.1) 56(84) bytes of data.
64 bytes from 10.1.1.1: icmp_seq=1 ttl=64 time=0.409 ms
64 bytes from 10.1.1.1: icmp_seq=2 ttl=64 time=0.481 ms
^C
--- 10.1.1.1 ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 999ms
rtt min/avg/max/mdev = 0.409/0.445/0.481/0.036 ms
version:
kube#kubernetes-master:~$ kubectl version
Client Version: version.Info{Major:"1", Minor:"4", GitVersion:"v1.4.5", GitCommit:"5a0a696437ad35c133c0c8493f7e9d22b0f9b81b", GitTreeState:"clean", BuildDate:"2016-10-29T01:38:40Z", GoVersion:"go1.6.3", Compiler:"gc", Platform:"linux/amd64"}
Server Version: version.Info{Major:"1", Minor:"4", GitVersion:"v1.4.5", GitCommit:"5a0a696437ad35c133c0c8493f7e9d22b0f9b81b", GitTreeState:"clean", BuildDate:"2016-10-29T01:32:42Z", GoVersion:"go1.6.3", Compiler:"gc", Platform:"linux/amd64"}
kubernetes-minion-2 (10.244.2.1):
(Per #der's response adding info from 10.244.2.1)
kube#kubernetes-minion-2:~$ ip addr show cbr0
5: cbr0: <BROADCAST,MULTICAST,PROMISC,UP,LOWER_UP> mtu 1500 qdisc htb state UP group default
link/ether 8a:ef:b5:fc:28:f4 brd ff:ff:ff:ff:ff:ff
inet 10.244.2.1/24 scope global cbr0
valid_lft forever preferred_lft forever
inet6 fe80::38b5:44ff:fe8a:6d79/64 scope link
valid_lft forever preferred_lft forever
kube#kubernetes-minion-2:~$ ping google.com
PING google.com (216.58.192.14) 56(84) bytes of data.
64 bytes from nuq04s29-in-f14.1e100.net (216.58.192.14): icmp_seq=1 ttl=52 time=11.8 ms
64 bytes from nuq04s29-in-f14.1e100.net (216.58.192.14): icmp_seq=2 ttl=52 time=11.6 ms
64 bytes from nuq04s29-in-f14.1e100.net (216.58.192.14): icmp_seq=3 ttl=52 time=10.4 ms
^C
--- google.com ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2002ms
rtt min/avg/max/mdev = 10.477/11.343/11.878/0.624 ms
kube#kubernetes-minion-2:~$ ping 10.1.1.1
PING 10.1.1.1 (10.1.1.1) 56(84) bytes of data.
64 bytes from 10.1.1.1: icmp_seq=1 ttl=64 time=0.369 ms
64 bytes from 10.1.1.1: icmp_seq=2 ttl=64 time=0.456 ms
64 bytes from 10.1.1.1: icmp_seq=3 ttl=64 time=0.442 ms
^C
--- 10.1.1.1 ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 1998ms
rtt min/avg/max/mdev = 0.369/0.422/0.456/0.041 ms
kube#kubernetes-minion-2:~$ netstat -r
Kernel IP routing table
Destination Gateway Genmask Flags MSS Window irtt Iface
default 10.1.1.1 0.0.0.0 UG 0 0 0 eth0
10.1.1.0 * 255.255.255.0 U 0 0 0 eth0
10.244.0.0 kubernetes-mini 255.255.255.0 UG 0 0 0 eth0
10.244.1.0 kubernetes-mini 255.255.255.0 UG 0 0 0 eth0
10.244.2.0 * 255.255.255.0 U 0 0 0 cbr0
10.244.3.0 kubernetes-mini 255.255.255.0 UG 0 0 0 eth0
172.17.0.0 * 255.255.0.0 U 0 0 0 docker0
kube#kubernetes-minion-2:~$ routel
target gateway source proto scope dev tbl
default 10.1.1.1 eth0
10.1.1.0 24 10.1.1.86 kernel link eth0
10.244.0.0 24 10.1.1.88 eth0
10.244.1.0 24 10.1.1.87 eth0
10.244.2.0 24 10.244.2.1 kernel link cbr0
10.244.3.0 24 10.1.1.85 eth0
172.17.0.0 16 172.17.0.1 kernel linkdocker0
10.1.1.0 broadcast 10.1.1.86 kernel link eth0 local
10.1.1.86 local 10.1.1.86 kernel host eth0 local
10.1.1.255 broadcast 10.1.1.86 kernel link eth0 local
10.244.2.0 broadcast 10.244.2.1 kernel link cbr0 local
10.244.2.1 local 10.244.2.1 kernel host cbr0 local
10.244.2.255 broadcast 10.244.2.1 kernel link cbr0 local
127.0.0.0 broadcast 127.0.0.1 kernel link lo local
127.0.0.0 8 local 127.0.0.1 kernel host lo local
127.0.0.1 local 127.0.0.1 kernel host lo local
127.255.255.255 broadcast 127.0.0.1 kernel link lo local
172.17.0.0 broadcast 172.17.0.1 kernel linkdocker0 local
172.17.0.1 local 172.17.0.1 kernel hostdocker0 local
172.17.255.255 broadcast 172.17.0.1 kernel linkdocker0 local
::1 local kernel lo
fe80:: 64 kernel eth0
fe80:: 64 kernel cbr0
fe80:: 64 kernel veth6129284
default unreachable kernel lo unspec
::1 local none lo local
fe80::250:56ff:fe8e:d580 local none lo local
fe80::38b5:44ff:fe8a:6d79 local none lo local
fe80::88ef:b5ff:fefc:28f4 local none lo local
ff00:: 8 eth0 local
ff00:: 8 cbr0 local
ff00:: 8 veth6129284 local
default unreachable kernel lo unspec
How can I diagnose what is going on here?
thanks!
Turns out this is an issue with the default nat routing rules on the minions
$ iptables –t nat –vnxL
...
...
Chain POSTROUTING (policy ACCEPT 0 packets, 0 bytes)
pkts bytes target prot opt in out source destination
...
80 4896 MASQUERADE all -- * * 0.0.0.0/0 !10.0.0.0/8 /* kubelet: SNAT outbound cluster traffic */ ADDRTYPE match dst-type !LOCAL
...
...
This shows that all traffic coming from the 10.x.x.x network gets ignored by the postrouting rules.
If anyone runs across this fix it with:
$ iptables -t nat -I POSTROUTING 1 -s 10.244.0.0/16 -d 10.1.1.1/32 -j MASQUERADE
where 10.244.x.x/16 is the container network and 10.1.1.1 is the gateway ip
First, figure out what's up with kubernetes-mini. Do on it what you've done with the 2 nodes you've shown us.
All traffic between 10.1.1.0 and 10.244.2.0 goes through it. It, however, may have a bad route for the 10.1.1.0 net.
I'm setting up Firewall with a CentOs 6.0 for testing. I'm doing this on two virtualmachines.
First VM (Firewall) has 2 interface:
eth0 - connected to NAT with 10.0.2.10, access to internet
eth1 - connected to local vm network with 20.0.0.1
Second VM (Server) has 1 interface:
eth0 - connected to local vm network with 20.0.0.2, GATEWAY 20.0.0.1.
They both have static ip's and dns. What I want to do is that Server have inet access via Firewall VM, to do that I've done those configurations:
VM1-Firewall:
/etc/sysctl.conf net.ipv4.ip_forward 1
iptables -t nat -A POSTROUTING --out-interface eth0 -j MASQUERADE
iptables -A FORWARD --in-interface eth1 -j ACCEPT
VM2-Server:
Just set that the gateway is the firewall 20.0.0.1 and DNS is 8.8.8.8
When I try to ping, for example, 8.8.8.8 it says Destination Host Prohibited.
Could anyone tell me what I'm doing wrong? I think it's iptables doesnt redirect traffic from eth1 to eth0 but it should do with this config, no?
Thanks a lot!
Due to default denying firewall policy you should rather use
iptables -t nat -I POSTROUTING --out-interface eth0 -j MASQUERADE
iptables -I FORWARD --in-interface eth1 -j ACCEPT
-A option appends the rule at the end of iptables chain. The default drop policy will firstly drop the packet and ignore further matching rules.