Re: [9fans] Static ip configuration for a standalone cpu server in qemu on Linux

[Alexander Kapshuk <alexander.kapshuk@gmail.com>]

Thanks Hiro and Bakul for your prompt responses.

Here's what I've got to report...

I brought tap0 as user root:
ip link set dev tap0 up

ip addr show dev tap0
4: tap0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast
state UP group default qlen 1000
    link/ether c6:1c:63:d9:91:1d brd ff:ff:ff:ff:ff:ff
    inet 10.0.0.1/24 scope global tap0
       valid_lft forever preferred_lft forever
    inet6 fe80::c41c:63ff:fed9:911d/64 scope link
       valid_lft forever preferred_lft forever

ping -c4 10.0.0.2
PING 10.0.0.2 (10.0.0.2) 56(84) bytes of data.
>From 10.0.0.1 icmp_seq=1 Destination Host Unreachable
>From 10.0.0.1 icmp_seq=2 Destination Host Unreachable
>From 10.0.0.1 icmp_seq=3 Destination Host Unreachable
>From 10.0.0.1 icmp_seq=4 Destination Host Unreachable

--- 10.0.0.2 ping statistics ---
4 packets transmitted, 0 received, +4 errors, 100% packet loss, time 75ms
pipe 4

# In qemu I got this output:
arpreq: 10.0.0.1 also has ether address c61c63d9911d

# Tcpdump output on Linux host:
tcpdump -nS -vv -i tap0
tcpdump: listening on tap0, link-type EN10MB (Ethernet), capture size
262144 bytes
22:12:40.302180 IP6 (hlim 255, next-header ICMPv6 (58) payload length:
16) fe80::c41c:63ff:fed9:911d > ff02::2: [icmp6 sum ok] ICMP6, router
solicitation, length 16
  source link-address option (1), length 8 (1): c6:1c:63:d9:91:1d
    0x0000:  c61c 63d9 911d
22:12:47.874535 IP (tos 0x0, ttl 1, id 18152, offset 0, flags [DF],
proto UDP (17), length 195)
    10.0.0.1.49968 > 239.255.255.250.1900: [udp sum ok] UDP, length 167
22:12:48.875587 IP (tos 0x0, ttl 1, id 18675, offset 0, flags [DF],
proto UDP (17), length 195)
    10.0.0.1.49968 > 239.255.255.250.1900: [udp sum ok] UDP, length 167
22:12:49.875963 IP (tos 0x0, ttl 1, id 19386, offset 0, flags [DF],
proto UDP (17), length 195)
    10.0.0.1.49968 > 239.255.255.250.1900: [udp sum ok] UDP, length 167
22:12:50.876052 IP (tos 0x0, ttl 1, id 20194, offset 0, flags [DF],
proto UDP (17), length 195)
    10.0.0.1.49968 > 239.255.255.250.1900: [udp sum ok] UDP, length 167
22:13:25.356189 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has
10.0.0.2 tell 10.0.0.1, length 28
22:13:26.382153 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has
10.0.0.2 tell 10.0.0.1, length 28
22:13:27.406149 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has
10.0.0.2 tell 10.0.0.1, length 28
22:13:28.430247 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has
10.0.0.2 tell 10.0.0.1, length 28
22:13:29.454154 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has
10.0.0.2 tell 10.0.0.1, length 28
22:13:30.478150 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has
10.0.0.2 tell 10.0.0.1, length 28

Thanks.
On Sat, Aug 25, 2018 at 9:29 PM Bakul Shah <bakul@bitblocks.com> wrote:
>
> On Sat, 25 Aug 2018 14:20:44 +0300 Alexander Kapshuk <alexander.kapshuk@gmail.com> wrote:
> > I am trying to follow the instructions given here:
> >
> > http://fqa.9front.org/fqa3.html#3.3.1.4.4
> > 3.3.1.4.4 - Linux TAP
> >
> > Here's what I've done so far:
> > (1). Set up a tap0 device as user root:
> > ip tuntap add dev tap0 mode tap user sasha
> > ip address add 10.0.0.1/24 dev tap0
> >
> > ip addr show dev tap0
> > 4: tap0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group
> > default qlen 1000
> >     link/ether c6:1c:63:d9:91:1d brd ff:ff:ff:ff:ff:ff
> >     inet 10.0.0.1/24 scope global tap0
> >        valid_lft forever preferred_lft forever
>
> I see that tap0 state is DOWN. Try bringing it up.
> If that still doesn't work, run
>     tcpdump -ni tap0
> and tell us what you discover.
>