===file "/etc/network/interfaces" in host:===
auto lo
iface lo inet loopback
iface enp2s0 inet manual
auto br0
iface br0 inet dhcp
bridge_stp off
bridge_maxwait 0
bridge_fd 0
pre-up ip tuntap add dev tap1 mode tap user cnliou
pre-up ip link set tap1 up
post-down ip link set tap1 down
post-down ip tuntap del dev tap1 mode tap
pre-up ip tuntap add dev tap2 mode tap user cnliou
pre-up ip link set tap2 up
post-down ip link set tap2 down
post-down ip tuntap del dev tap2 mode tap
bridge_ports all tap1 tap2
==="ip address" in host:===
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
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: enp2s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master
br0 state UP group default qlen 1000
link/ether ec:a8:6b:2a:01:20 brd ff:ff:ff:ff:ff:ff
6: tap1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master br0
state UP group default qlen 1000
link/ether a2:43:f5:1e:2a:55 brd ff:ff:ff:ff:ff:ff
7: tap2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master br0
state UP group default qlen 1000
link/ether 56:63:da:29:51:02 brd ff:ff:ff:ff:ff:ff
8: br0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group
default qlen 1000
link/ether 52:f3:b3:de:05:71 brd ff:ff:ff:ff:ff:ff
inet 192.168.1.101/24 brd 192.168.1.255 scope global dynamic br0
valid_lft 85194sec preferred_lft 85194sec
inet6 2001:b011:2012:3d62:50f3:b3ff:fede:571/64 scope global dynamic
mngtmpaddr
valid_lft 86324sec preferred_lft 86324sec
inet6 fe80::50f3:b3ff:fede:571/64 scope link
valid_lft forever preferred_lft forever
===Launch guest A in host:===
qemu-system-x86_64 -m 1.5G -cpu max -machine pc,accel=kvm -drive
file=debian1.img,if=none,id=drive0 -device virtio-blk,drive=drive0,bootindex=0
-net nic,model=virtio -net tap,ifname=tap1,script=no,downscript=no
===Launch guest B in host:===
qemu-system-x86_64 -m 1.5G -cpu max -machine pc,accel=kvm -drive
file=debian2.img,if=none,id=drive0 -device virtio-blk,drive=drive0,bootindex=0
-net nic,model=virtio -net tap,ifname=tap2,script=no,downscript=no
===file "/etc/network/interfaces" in guest A:===
auto lo
iface lo inet loopback
auto enp0s3
iface enp0s3 inet static
address 192.168.1.11/32
gateway 192.168.1.1
==="ip address" in guest 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
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: ens3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP
group default qlen 1000
link/ether 52:54:00:12:34:56 brd ff:ff:ff:ff:ff:ff
altname enp0s3
inet 192.168.1.11/32 brd 192.168.1.11 scope global enp0s3
valid_lft forever preferred_lft forever
inet6 2001:b011:2012:3d62:5054:ff:fe12:3456/64 scope global dynamic
mngtmpaddr
valid_lft 86362sec preferred_lft 86362sec
inet6 fe80::5054:ff:fe12:3456/64 scope link
valid_lft forever preferred_lft forever
==="ip route" in guest A:===
default via 192.168.1.1 dev ens3 onlink
===file "/etc/network/interfaces" in guest B:===
auto lo
iface lo inet loopback
auto enp0s3
iface enp0s3 inet static
address 192.168.1.12/32
gateway 192.168.1.1
==="ping 192.168.1.11" in host:===
PING 192.168.1.11 (192.168.1.11) 56(84) bytes of data.
64 bytes from 192.168.1.11: icmp_seq=1 ttl=64 time=0.189 ms
64 bytes from 192.168.1.11: icmp_seq=2 ttl=64 time=0.208 ms
--- 192.168.1.11 ping statistics ---
4 packets transmitted, 4 received, 0% packet loss, time 3051ms
rtt min/avg/max/mdev = 0.189/0.194/0.208/0.007 ms
==="ping 192.168.1.12" in host (test 1):===
PING 192.168.1.12 (192.168.1.12) 56(84) bytes of data.
64 bytes from 192.168.1.12: icmp_seq=1 ttl=63 time=0.756 ms
64 bytes from 192.168.1.12: icmp_seq=2 ttl=64 time=0.194 ms
64 bytes from 192.168.1.12: icmp_seq=7 ttl=64 time=0.182 ms
64 bytes from 192.168.1.12: icmp_seq=8 ttl=64 time=0.178 ms
==="ping 192.168.1.12" in host (test 2):===
PING 192.168.1.12 (192.168.1.12) 56(84) bytes of data.
64 bytes from 192.168.1.12: icmp_seq=10 ttl=63 time=0.773 ms
64 bytes from 192.168.1.12: icmp_seq=11 ttl=64 time=0.209 ms
64 bytes from 192.168.1.12: icmp_seq=12 ttl=64 time=0.208 ms
==="ping 192.168.1.101" in guest A:===
PING 192.168.1.101 (192.168.1.101) 56(84) bytes of data.
64 bytes from 192.168.1.101: icmp_seq=1 ttl=64 time=42.2 ms
64 bytes from 192.168.1.101: icmp_seq=2 ttl=64 time=0.625 ms
>From 192.168.1.1: icmp_seq=2 Redirect Host(New nexthop: 192.168.1.101)
64 bytes from 192.168.1.101: icmp_seq=3 ttl=64 time=0.997 ms
64 bytes from 192.168.1.101: icmp_seq=4 ttl=64 time=0.184 ms
==="ping 192.168.1.101" in guest B:===
PING 192.168.1.101 (192.168.1.101) 56(84) bytes of data.
64 bytes from 192.168.1.101: icmp_seq=1 ttl=64 time=45.6 ms
64 bytes from 192.168.1.101: icmp_seq=2 ttl=64 time=0.182 ms
==="ping 192.168.1.12" in guest A (test 1):===
PING 192.168.1.12 (192.168.1.12) 56(84) bytes of data.
>From 192.168.1.1: icmp_seq=33 Redirect Host(New nexthop: 192.168.1.12)
>From 192.168.1.11 icmp_seq=43 Destination Host Unreachable
>From 192.168.1.11 icmp_seq=44 Destination Host Unreachable
==="ping 192.168.1.12" in guest A (test 2):===
PING 192.168.1.12 (192.168.1.12) 56(84) bytes of data.
>From 192.168.1.1: icmp_seq=2 Redirect Host(New nexthop: 192.168.1.12)
>From 192.168.1.11 icmp_seq=11 Destination Host Unreachable
>From 192.168.1.11 icmp_seq=12 Destination Host Unreachable
==="ping 192.168.1.12" in guest A (test 3):===
PING 192.168.1.12 (192.168.1.12) 56(84) bytes of data.
>From 192.168.1.1: icmp_seq=2 Redirect Host(New nexthop: 192.168.1.12)
>From 192.168.1.1: icmp_seq=3 Redirect Host(New nexthop: 192.168.1.12)
==="ping 192.168.1.12" in guest A (test 4):===
(no response)
==="ping 192.168.1.11" in guest B (test 1):===
PING 192.168.1.11 (192.168.1.12) 56(84) bytes of data.
>From 192.168.1.1: icmp_seq=33 Redirect Host(New nexthop: 192.168.1.11)
==="ping 192.168.1.11" in guest B (test 2):===
PING 192.168.1.11 (192.168.1.11) 56(84) bytes of data.
>From 192.168.1.12 icmp_seq=1 Destination Host Unreachable
>From 192.168.1.12 icmp_seq=2 Destination Host Unreachable
==="scp MyFile root@192.168.1.101" in both guest A and guest B: successful====
successful:
==="ssh 192.168.1.12" from host (test 1):===
"du": successful
"exit": took a long time to logout
==="ssh 192.168.1.12" from host (test 2):===
It took a long time for "password" prompt to show up.
==="scp MyFile root@192.168.1.12:/tmp" from host:===
(no response)
It looks to me that the only reliable and fast communications are those
commands (ping, scp, ssh) initialiated from within guests A and B to the host.
Best regards,
CN
