After upgrading from Ubuntu 16.04 LTS to the new 18.04, even before rebooting the system, ping won't work anymore. It just hangs indefinitely and doesn't matter if I ping a DNS, an IP or even the IP of a CentOS VM running in the same system. Now neither SSH is working. When I try to SSH into the VM, it hangs for a while up to the timeout.
Everything was working before.
I have internet working perfectly. I can curl anything, browse any website, install anything with apt. The only problem is that I need SSH working and it seems the ping problem is related to it.
I already checked my firewall, which is not rejecting anything, my ethernet configuration, which is auto by DHCP, and my hosts, which didn`t change from before upgrading.
My ethernet configuration:
> ifconfig | grep 'eno1:\|lo:' -A6 eno1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 inet 10.121.3.143 netmask 255.255.255.0 broadcast 10.121.3.255 inet6 fe80::4ff2:e79a:8a81:93e1 prefixlen 64 scopeid 0x20<link> ether dc:4a:3e:7d:f1:33 txqueuelen 1000 (Ethernet) RX packets 1007708 bytes 1386860256 (1.3 GB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 335796 bytes 30111660 (30.1 MB) -- lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536 inet 127.0.0.1 netmask 255.0.0.0 inet6 ::1 prefixlen 128 scopeid 0x10<host> loop txqueuelen 1000 (Local Loopback) RX packets 3319 bytes 313220 (313.2 KB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 3319 bytes 313220 (313.2 KB) > ▮
My route configuration:
> route Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface default _gateway 0.0.0.0 UG 100 0 0 eno1 10.121.3.0 0.0.0.0 255.255.255.0 U 100 0 0 eno1 link-local 0.0.0.0 255.255.0.0 U 1000 0 0 eno1 192.168.123.0 0.0.0.0 255.255.255.0 U 0 0 0 virbr0 > ▮
My hosts configuration:
> cat /etc/hosts 127.0.0.1 localhost > ▮
My firewall configuration:
> sudo iptables -S -P FORWARD ACCEPT -P OUTPUT ACCEPT -A INPUT -i virbr0 -p udp -m udp --dport 53 -j ACCEPT -A INPUT -i virbr0 -p tcp -m tcp --dport 53 -j ACCEPT -A INPUT -i virbr0 -p udp -m udp --dport 67 -j ACCEPT -A INPUT -i virbr0 -p tcp -m tcp --dport 67 -j ACCEPT -A FORWARD -d 192.168.123.0/24 -o virbr0 -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT -A FORWARD -s 192.168.123.0/24 -i virbr0 -j ACCEPT -A FORWARD -i virbr0 -o virbr0 -j ACCEPT -A OUTPUT -o virbr0 -p udp -m udp --dport 68 -j ACCEPT > ▮
Here is the ping output to my VM's ip (192.168.122.12), which is on and I can access through virt-manager no problem:
> ping 192.168.122.12 PING 192.168.122.12 (192.168.122.12) 56(84) bytes of data. ▮
It stays there indefinitely.
However, it works if I ping localhost:
> ping localhost PING localhost (127.0.0.1) 56(84) bytes of data. 64 bytes from localhost (127.0.0.1): icmp_seq=1 ttl=64 time=0.068 ms 64 bytes from localhost (127.0.0.1): icmp_seq=2 ttl=64 time=0.068 ms 64 bytes from localhost (127.0.0.1): icmp_seq=3 ttl=64 time=0.068 ms ^C --- localhost ping statistics --- 3 packets transmitted, 3 received, 0% packet loss, time 2052ms rtt min/avg/max/mdev = 0.068/0.068/0.068/0.000 ms > ▮
Pinging to another machine on the same network also works:
> ping 10.121.3.41 PING 10.121.3.41 (10.121.3.41) 56(84) bytes of data. 64 bytes from 10.121.3.41: icmp_seq=1 ttl=64 time=0.580 ms 64 bytes from 10.121.3.41: icmp_seq=2 ttl=64 time=0.313 ms 64 bytes from 10.121.3.41: icmp_seq=3 ttl=64 time=0.277 ms 64 bytes from 10.121.3.41: icmp_seq=4 ttl=64 time=0.530 ms 64 bytes from 10.121.3.41: icmp_seq=5 ttl=64 time=0.248 ms ^C --- 10.121.3.41 ping statistics --- 5 packets transmitted, 5 received, 0% packet loss, time 4097ms rtt min/avg/max/mdev = 0.248/0.389/0.580/0.139 ms > ▮
Pinging to an external website won't:
> ping www.google.com PING www.google.com (18.104.22.168) 56(84) bytes of data. ▮
But that might be another issue related with my network manager. Again, I can browser no problem.
Here is the SSH output:
> ssh 192.168.122.12 ▮
After some time:
> ssh 192.168.122.12 ssh: connect to host 192.168.122.12 port 22: Connection timed out > ▮
Yes, the VM's port 22 is open for SSH connections (everything was working before the update):
(VM) > netstat -tuplen | grep "servers\|Proto\|:22 " Active Internet connections (only servers) Proto Recv-Q Send-Q Local Address Foreign Address State User Inode PID/program tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 0 18112 1295/sshd tcp6 0 0 :::22 :::* LISTEN 0 18114 1295/sshd (VM) > ▮
Does anyone have any idea about how can I fix it?
* EDIT / SOLUTION *
Alright, forget it. I didn't check my VM's ip. Suddenly, it changed to another ip I don't know why. Checking ifconfig in VM gave me the right ip address.
I will keep the post for other people who may also forget to check it.
Thank you anyway.