Re: [Xen-users] Re: Guests stops at "Sending DHCP requests ..."

[Flavio <fbcyborg@xxxxxxxxx>]

2009/11/22 Boris Derzhavets <bderzhavets@xxxxxxxxx>
> Usually i ran :-
> # tcpdump -vv -s 1600 | tee log
> DHCPDISCOVER sends UDP packets.
> I cannot see in the report CHECKSUMS diagnostics.
I did it too, and here's what I got:
13:45:58.763166 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto
TCP (6), length 52) 192.168.1.103.45487 >
host11-2-dynamic.81-71-r.retail.telecomitalia.it.7876: ., cksum 0x54b9
(correct), 135:135(0) ack 153 win 54 <nop,nop,timestamp 4294942296
10921>
13:45:59.014636 IP (tos 0x0, ttl 1, id 7663, offset 0, flags [DF],
proto IGMP (2), length 36, options (RA)) 192.168.1.254 >
ALL-SYSTEMS.MCAST.NET: igmp query v3 [max resp time 10s]
13:45:59.014829 IP (tos 0x0, ttl 64, id 40600, offset 0, flags [DF],
proto UDP (17), length 68) 192.168.1.103.42839 > nst.tin.it.domain:
[udp sum ok] 42104+ PTR? 1.0.0.224.in-addr.arpa. (40)
13:45:59.103561 IP (tos 0x0, ttl 54, id 30220, offset 0, flags [none],
proto UDP (17), length 268) nst.tin.it.domain > 192.168.1.103.42839:
[udp sum ok] 42104 q: PTR? 1.0.0.224.in-addr.arpa. 1/3/5
1.0.0.224.in-addr.arpa. PTR ALL-SYSTEMS.MCAST.NET. ns:
224.in-addr.arpa. NS nic.near.NET., 224.in-addr.arpa. NS
strul.stupi.se., 224.in-addr.arpa. NS flag.ep.NET. ar: flag.ep.NET. A
flag.ip4.int, nic.near.NET. A pscgate.progress.com, strul.stupi.se. A
Strul.Stupi.SE, strul.stupi.se. A Strul.Stupi.SE, strul.stupi.se. AAAA
2001:440:1880:1002::1 (240)
13:45:59.103698 IP (tos 0x0, ttl 64, id 40622, offset 0, flags [DF],
proto UDP (17), length 70) 192.168.1.103.58245 > nst.tin.it.domain:
[udp sum ok] 60433+ PTR? 13.4.32.198.in-addr.arpa. (42)
13:45:59.689435 arp who-has 192.168.1.100 tell 192.168.1.254
13:46:02.821471 arp who-has 192.168.1.100 tell 192.168.1.254
13:46:03.819362 arp who-has 192.168.1.100 tell 192.168.1.254
13:46:04.112221 IP (tos 0x0, ttl 64, id 41874, offset 0, flags [DF],
proto UDP (17), length 70) 192.168.1.103.45661 >
dns-tin.virgilio.net.domain: [udp sum ok] 60433+ PTR?
13.4.32.198.in-addr.arpa. (42)
13:46:04.819336 arp who-has 192.168.1.100 tell 192.168.1.254
13:46:05.802866 IP6 (hlim 1, next-header Options (0) payload length:
36) :: > ff02::16: HBH (rtalert: 0x0000) (padn)[icmp6 sum ok] ICMP6,
multicast listener report v2, length 28, 1 group record(s) [gaddr
ff02::1:ff14:4841 to_ex { }]
13:46:05.820787 arp who-has 192.168.1.100 tell 192.168.1.254
13:46:05.987035 IP (tos 0x0, ttl 51, id 21548, offset 0, flags [none],
proto TCP (6), length 105) mu-in-f18.1e100.net.https >
192.168.1.103.51438: P, cksum 0x7d30 (correct),
3312971843:3312971896(53) ack 1044044669 win 416 <nop,nop,timestamp
2037197290 4294937073>
13:46:05.987076 IP (tos 0x0, ttl 64, id 36270, offset 0, flags [DF],
proto TCP (6), length 52) 192.168.1.103.51438 >
mu-in-f18.1e100.net.https: ., cksum 0x773f (correct), 1:1(0) ack 53
win 501 <nop,nop,timestamp 4294944103 2037197290>
13:46:06.366894 IP6 (hlim 255, next-header ICMPv6 (58) payload length:
24) :: > ff02::1:ff14:4841: [icmp6 sum ok] ICMP6, neighbor
solicitation, length 24, who has fe80::216:3eff:fe14:4841
13:46:06.801912 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto
UDP (17), length 576) 0.0.0.0.bootpc > 255.255.255.255.bootps: [no
cksum] BOOTP/DHCP, Request from 00:16:3e:14:48:41 (oui Unknown),
length 548, xid 0xfbd8e62c, Flags [none] (0x0000)
          Client-Ethernet-Address 00:16:3e:14:48:41 (oui Unknown)
          Vendor-rfc1048 Extensions
            Magic Cookie 0x63825363
            DHCP-Message Option 53, length 1: Request
            Server-ID Option 54, length 4: 127.0.255.255
            Requested-IP Option 50, length 4: 255.255.255.255
            Parameter-Request Option 55, length 8:
              Subnet-Mask, Default-Gateway, Domain-Name-Server, Hostname
              Domain-Name, RP, MTU, YD
13:46:06.819316 arp who-has 192.168.1.100 tell 192.168.1.254
13:46:07.366893 IP6 (hlim 255, next-header ICMPv6 (58) payload length:
16) fe80::216:3eff:fe14:4841 > ff02::2: [icmp6 sum ok] ICMP6, router
solicitation, length 16
          source link-address option (1), length 8 (1): 00:16:3e:14:48:41
            0x0000:  0016 3e14 4841
13:46:07.819280 arp who-has 192.168.1.100 tell 192.168.1.254
13:46:09.120203 IP (tos 0x0, ttl 64, id 40623, offset 0, flags [DF],
proto UDP (17), length 70) 192.168.1.103.58245 > nst.tin.it.domain:
[udp sum ok] 60433+ PTR? 13.4.32.198.in-addr.arpa. (42)
13:46:09.155953 IP (tos 0x0, ttl 54




> Anyway, i would try to disable checksum offloading just for one DomU. Bad 
> checksum
> causes packet to be discarded at your router (ADSL modem).
I don't know how to do that, excuse me! :)

Thank you,

Flavio

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