Re: Networking problems

[Matteo Beccati <php%beccati.com@localhost>]

Jonathan A. Kollasch ha scritto:
> > The domU seems perfectly working, but I'm unable to have a working 
> > network configuration. If I try to ping any machine in the bridged 
> > network I receive DUP! answers, but the same doesn't happen when trying 
>
> I don't get duplicate replies in my setup.

In fact it seems very weird, and I guess that it could be related to the 
problem I'm having.

> Some more investigation would be appreciated.  Verify that the packets
> are flowing to the right place at all tcpdump-able interfaces, (the -e
> flag will be useful).  Also check for appropriate entries in the ARP
> tables of the various machines.
>
> I'd venture a guess that the Xen (virtual) machines are at most
> only half of this problem.

tcpdump on domU
---------------
# tcpdump -e port smtp
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on xennet0, link-type EN10MB (Ethernet), capture size 96 bytes
09:19:27.600829 ab:00:00:50:02:f1 > 00:05:5d:e9:f4:50, ethertype IPv4 
(0x0800), length 78: IP 192.168.1.121.65512 > 192.168.1.100.smtp: S 
2995693514:2995693514(0) win 32768 <mss 1460,nop,wscale 
0,sackOK,nop,nop,nop,nop,timestamp 0 0>
09:19:27.601122 00:05:5d:e9:f4:50 > ab:00:00:50:02:f1, ethertype IPv4 
(0x0800), length 78: IP 192.168.1.100.smtp > 192.168.1.121.65512: S 
3474970826:3474970826(0) ack 2995693515 win 32768 <mss 1460,nop,wscale 
0,nop,nop,timestamp 0 0,sackOK,nop,nop>
09:19:27.601706 00:0f:3d:09:72:91 > ab:00:00:50:02:f1, ethertype IPv4 
(0x0800), length 78: IP 192.168.1.100.smtp > 192.168.1.121.65512: S 
3474970826:3474970826(0) ack 2995693515 win 32768 <mss 1460,nop,wscale 
0,nop,nop,timestamp 0 0,sackOK,nop,nop>

tcpdump on dom0
---------------
# tcpdump -e -i xvif1.0 port smtp
tcpdump: WARNING: xvif1.0: no IPv4 address assigned
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on xvif1.0, link-type EN10MB (Ethernet), capture size 96 bytes
09:22:29.268514 ab:00:00:50:02:f1 > 00:05:5d:e9:f4:50, ethertype IPv4 
(0x0800), length 78: IP 192.168.1.121.65511 > 192.168.1.100.smtp: S 
516453751:516453751(0) win 32768 <mss 1460,nop,wscale 
0,sackOK,nop,nop,nop,nop,timestamp 0 0>
09:22:29.268686 00:05:5d:e9:f4:50 > ab:00:00:50:02:f1, ethertype IPv4 
(0x0800), length 78: IP 192.168.1.100.smtp > 192.168.1.121.65511: S 
1002670117:1002670117(0) ack 516453752 win 32768 <mss 1460,nop,wscale 
0,nop,nop,timestamp 0 0,sackOK,nop,nop>
09:22:29.269206 00:0f:3d:09:72:91 > ab:00:00:50:02:f1, ethertype IPv4 
(0x0800), length 78: IP 192.168.1.100.smtp > 192.168.1.121.65511: S 
1002670117:1002670117(0) ack 516453752 win 32768 <mss 1460,nop,wscale 
0,nop,nop,timestamp 0 0,sackOK,nop,nop>

# tcpdump -e -i ste0 port smtp
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on ste0, link-type EN10MB (Ethernet), capture size 96 bytes
09:24:00.111289 00:05:5d:e9:f4:50 > ab:00:00:50:02:f1, ethertype IPv4 
(0x0800), length 78: IP 192.168.1.100.smtp > 192.168.1.121.65510: S 
4074556107:4074556107(0) ack 3582402440 win 32768 <mss 1460,nop,wscale 
0,nop,nop,timestamp 0 0,sackOK,nop,nop>
09:24:00.111787 00:0f:3d:09:72:91 > ab:00:00:50:02:f1, ethertype IPv4 
(0x0800), length 78: IP 192.168.1.100.smtp > 192.168.1.121.65510: S 
4074556107:4074556107(0) ack 3582402440 win 32768 <mss 1460,nop,wscale 
0,nop,nop,timestamp 0 0,sackOK,nop,nop>
09:24:03.110933 00:05:5d:e9:f4:50 > ab:00:00:50:02:f1, ethertype IPv4 
(0x0800), length 78: IP 192.168.1.100.smtp > 192.168.1.121.65510: S 
4074556107:4074556107(0) ack 3582402440 win 32768 <mss 1460,nop,wscale 
0,nop,nop,timestamp 6 0,sackOK,nop,nop>

# tcpdump -e -i bridge0 port smtp
tcpdump: BIOCSETIF: bridge0: Device not configured


arp on domU
-----------
# arp -a
? (192.168.1.1) at 00:0f:3d:09:72:91 on xennet0
? (192.168.1.100) at 00:05:5d:e9:f4:50 on xennet0
? (192.168.1.200) at 00:13:d4:88:8e:50 on xennet0

arp on dom0
-----------
# arp -a
? (192.168.1.1) at 00:0f:3d:09:72:91 on ste0
? (192.168.1.121) at ab:00:00:50:02:f1 on ste0
? (192.168.1.200) at 00:13:d4:88:8e:50 on ste0


Best regards
--
Matteo Beccati
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