Hi,
I'm working in a NAT-PT and I'm having some trouble translating IPv4/IPv6 fragmented
packets.
I have the following setup:
+--------+ Seg.3 +--------+ Seg.2 +-------+ Seg.1 +-------+
| Host C |-------| NAT-PT |--------|Host B |-------|Host A |
| FreeBSD| | Linux | |FreeBSD| |Linux |
+--------+ +--------+ +-------+ +-------+
IPv6 IPv4 IPv4
MTU=1500 MTU=100 MTU=1500
When host A tries to reach host C, the fragmented packets are apparently well
translated by the NAT-PT router according to SIIT (RFC 2765). Looking with a sniffer
in segment 2 and 3, you see that each of the fragments are translated, I don't see any
error in the new IPv6 packets, but the IPv6 host doesn't seems to reensamble the
fragments, because the host never sends an ack back.
Whaty could it be happening? could it be an error in the translation procees that we
haven't found or an issue with the handling of IPv6 fragmented packets in FreeBSD?
Here I send the capture of the first packet and how is translated. The rest of the
fragments are translated in the same way:
Internet Protocol
Versi�n:4
Header Length: 20 bytes
DSF:0x10
Total Length:100 bytes
Identification: 0x02fc
Flags: 0x02
0 = Don�t fragment: no set
1 = More fragments : set
Fragment offset: 0
Time to live: 63
Protocol: TCP (0x06)
Header checksum: 0x95dd (correct)
Source: 192.168.1.2 (192.168.1.2)
Destination: 1.0.0.1 (1.0.0.1)
Transmission Control Protocol
Source Port: telnet (23)
Destination port : 1027
Sequence number : 3853395892
Next sequence number : 3853395940
Acknowledgement number: 3252790475
Header Length: 32 bytes
Flags: 0x0010 (ACK)
Windows size: 32844
Checksum: 0x904b
Options: (12 bytes)
Telnet
Data: vecore\r\n
Data: comcontrol\tifconfig\tmount_cd9660\tnewfs\t\t
Ej. Paquete fragmentado IPv6 traducido.
Internet Protocol Version 6
Version: 6
Traffic Class: 0x00
Flow Level: 0x00000
Payload Length: 88
Next Header: IPv6 Fragment (0x2c)
Hop Limit: 127
Source address: ::192.168.1.2
Destination Address: 3ffe:1ce1:2:0:200::2
Fragmentation Header
Next Header: TCP (0x06)
Offset: 0
More fragments: YES
Identification: 0x000002fc
Transmission Control Protocol
Source Port: telnet (23)
Destination port : 1027
Sequence number : 3853395892
Next sequence number : 3853395940
Acknowledgement number: 3252790475
Header Length: 32 bytes
Flags: 0x0010 (ACK)
Windows size: 32844
Checksum: 0xfd4f
Options: (12 bytes)
Telnet
Data: vecore\r\n
Data: comcontrol\tifconfig\tmount_cd9660\tnewfs\t\t
Thanks for any hint on this.
Cheers,
--
-------------------------------
Juan Luis Baptiste M.
Linux registered user #119248
http://www.merlinux.org
"we're back to the times
when men were men and
wrote their own drivers"
Linus Torvalds
-------------------------------
--
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