When we recently changed from a MS router (MN-500) to a Linksys router
(WRT54G) we stopped getting email from one customer. Putting the MS
router back in place restored our ability to receive email from that
customer but is not an acceptable solution. We are able to send email
to the customer with both routers.

I have sniffed packets and noted that there is a bad checksum in the
TCP header on certain packets from this customer. With the MS router,
we resend the message after a delay, the next message from the customer
has the correct checksum, and the email comes through. With the
Linksys router, we resend the message after a delay, but never get
another response from the customer. Packets from both routers are
included at the end of this post.

How can I configure our Linksys router such that we can receive emails
from this customer?

Thanks for your help
Mack McGhee


MS router
-----------------------------------------------------------------------------------------------------

No. Time Source Destination
Protocol Info
232 28.736314 166.67.49.252 192.168.1.22 TCP
54005 > smtp [SYN] Seq=0 Ack=0 Win=65535 Len=0 MSS=1460

Frame 232 (62 bytes on wire, 62 bytes captured)
Arrival Time: Dec 7, 2005 17:56:07.575662000
Time delta from previous packet: 28.736314000 seconds
Time since reference or first frame: 28.736314000 seconds
Frame Number: 232
Packet Length: 62 bytes
Capture Length: 62 bytes
Ethernet II, Src: 00:50:f2:c9:65:a4, Dst: 00:07:e9:d4:52:3c
Destination: 00:07:e9:d4:52:3c (Intel_d4:52:3c)
Source: 00:50:f2:c9:65:a4 (Microsof_c9:65:a4)
Type: IP (0x0800)
Internet Protocol, Src Addr: 166.67.49.252 (166.67.49.252), Dst Addr:
192.168.1.22 (192.168.1.22)
Version: 4
Header length: 20 bytes
Differentiated Services Field: 0x00 (DSCP 0x00: Default; ECN: 0x00)
Total Length: 48
Identification: 0xe1f0 (57840)
Flags: 0x04 (Don't Fragment)
Fragment offset: 0
Time to live: 110
Protocol: TCP (0x06)
Header checksum: 0x90d9 (correct)
Source: 166.67.49.252 (166.67.49.252)
Destination: 192.168.1.22 (192.168.1.22)
Transmission Control Protocol, Src Port: 54005 (54005), Dst Port: smtp
(25), Seq: 0, Ack: 0, Len: 0
Source port: 54005 (54005)
Destination port: smtp (25)
Sequence number: 0 (relative sequence number)
Header length: 28 bytes
Flags: 0x0002 (SYN)
Window size: 65535
Checksum: 0x7116 (correct)
Options: (8 bytes)
Maximum segment size: 1460 bytes
NOP
NOP
SACK permitted

0000 00 07 e9 d4 52 3c 00 50 f2 c9 65 a4 08 00 45 00
.....R<.P..e...E.
0010 00 30 e1 f0 40 00 6e 06 90 d9 a6 43 31 fc c0 a8
..0..@.n....C1...
0020 01 16 d2 f5 00 19 91 cd 13 2f 00 00 00 00 70 02
........../....p.
0030 ff ff 71 16 00 00 02 04 05 b4 01 01 04 02 ..q...........

No. Time Source Destination
Protocol Info
233 28.736341 192.168.1.22 166.67.49.252 TCP
smtp > 54005 [SYN, ACK] Seq=0 Ack=1 Win=17520 Len=0 MSS=1460

Frame 233 (62 bytes on wire, 62 bytes captured)
Arrival Time: Dec 7, 2005 17:56:07.575689000
Time delta from previous packet: 0.000027000 seconds
Time since reference or first frame: 28.736341000 seconds
Frame Number: 233
Packet Length: 62 bytes
Capture Length: 62 bytes
Ethernet II, Src: 00:07:e9:d4:52:3c, Dst: 00:50:f2:c9:65:a4
Destination: 00:50:f2:c9:65:a4 (Microsof_c9:65:a4)
Source: 00:07:e9:d4:52:3c (Intel_d4:52:3c)
Type: IP (0x0800)
Internet Protocol, Src Addr: 192.168.1.22 (192.168.1.22), Dst Addr:
166.67.49.252 (166.67.49.252)
Version: 4
Header length: 20 bytes
Differentiated Services Field: 0x00 (DSCP 0x00: Default; ECN: 0x00)
Total Length: 48
Identification: 0xd491 (54417)
Flags: 0x04 (Don't Fragment)
Fragment offset: 0
Time to live: 128
Protocol: TCP (0x06)
Header checksum: 0x8c38 (correct)
Source: 192.168.1.22 (192.168.1.22)
Destination: 166.67.49.252 (166.67.49.252)
Transmission Control Protocol, Src Port: smtp (25), Dst Port: 54005
(54005), Seq: 0, Ack: 1, Len: 0
Source port: smtp (25)
Destination port: 54005 (54005)
Sequence number: 0 (relative sequence number)
Acknowledgement number: 1 (relative ack number)
Header length: 28 bytes
Flags: 0x0012 (SYN, ACK)
Window size: 17520
Checksum: 0x55e9 (correct)
Options: (8 bytes)
Maximum segment size: 1460 bytes
NOP
NOP
SACK permitted
SEQ/ACK analysis
This is an ACK to the segment in frame: 232
The RTT to ACK the segment was: 0.000027000 seconds

0000 00 50 f2 c9 65 a4 00 07 e9 d4 52 3c 08 00 45 00
..P..e.....R<..E.
0010 00 30 d4 91 40 00 80 06 8c 38 c0 a8 01 16 a6 43
..0..@....8.....C
0020 31 fc 00 19 d2 f5 29 25 ad 86 91 cd 13 30 70 12
1.....)%.....0p.
0030 44 70 55 e9 00 00 02 04 05 b4 01 01 04 02 DpU...........

No. Time Source Destination
Protocol Info
234 28.779905 166.67.49.252 192.168.1.22 TCP
54005 > smtp [ACK] Seq=1 Ack=1 Win=65535 [CHECKSUM INCORRECT] Len=0

Frame 234 (60 bytes on wire, 60 bytes captured)
Arrival Time: Dec 7, 2005 17:56:07.619253000
Time delta from previous packet: 0.043564000 seconds
Time since reference or first frame: 28.779905000 seconds
Frame Number: 234
Packet Length: 60 bytes
Capture Length: 60 bytes
Ethernet II, Src: 00:50:f2:c9:65:a4, Dst: 00:07:e9:d4:52:3c
Destination: 00:07:e9:d4:52:3c (Intel_d4:52:3c)
Source: 00:50:f2:c9:65:a4 (Microsof_c9:65:a4)
Type: IP (0x0800)
Trailer: 000000000000
Internet Protocol, Src Addr: 166.67.49.252 (166.67.49.252), Dst Addr:
192.168.1.22 (192.168.1.22)
Version: 4
Header length: 20 bytes
Differentiated Services Field: 0x00 (DSCP 0x00: Default; ECN: 0x00)
Total Length: 40
Identification: 0xe1f3 (57843)
Flags: 0x04 (Don't Fragment)
Fragment offset: 0
Time to live: 111
Protocol: TCP (0x06)
Header checksum: 0x8fde (correct)
Source: 166.67.49.252 (166.67.49.252)
Destination: 192.168.1.22 (192.168.1.22)
Transmission Control Protocol, Src Port: 54005 (54005), Dst Port: smtp
(25), Seq: 1, Ack: 1, Len: 0
Source port: 54005 (54005)
Destination port: smtp (25)
Sequence number: 1 (relative sequence number)
Acknowledgement number: 1 (relative ack number)
Header length: 20 bytes
Flags: 0x0010 (ACK)
Window size: 65535
Checksum: 0xa59f (incorrect, should be 0xc71d)
SEQ/ACK analysis
This is an ACK to the segment in frame: 233
The RTT to ACK the segment was: 0.043564000 seconds

0000 00 07 e9 d4 52 3c 00 50 f2 c9 65 a4 08 00 45 00
.....R<.P..e...E.
0010 00 28 e1 f3 40 00 6f 06 8f de a6 43 31 fc c0 a8
..(..@.o....C1...
0020 01 16 d2 f5 00 19 91 cd 13 30 29 25 ad 87 50 10
..........0)%..P.
0030 ff ff a5 9f 00 00 00 00 00 00 00 00 ............

No. Time Source Destination
Protocol Info
264 31.969925 192.168.1.22 166.67.49.252 TCP
smtp > 54005 [SYN, ACK] Seq=0 Ack=1 Win=17520 Len=0 MSS=1460

Frame 264 (62 bytes on wire, 62 bytes captured)
Arrival Time: Dec 7, 2005 17:56:10.809273000
Time delta from previous packet: 3.190020000 seconds
Time since reference or first frame: 31.969925000 seconds
Frame Number: 264
Packet Length: 62 bytes
Capture Length: 62 bytes
Ethernet II, Src: 00:07:e9:d4:52:3c, Dst: 00:50:f2:c9:65:a4
Destination: 00:50:f2:c9:65:a4 (Microsof_c9:65:a4)
Source: 00:07:e9:d4:52:3c (Intel_d4:52:3c)
Type: IP (0x0800)
Internet Protocol, Src Addr: 192.168.1.22 (192.168.1.22), Dst Addr:
166.67.49.252 (166.67.49.252)
Version: 4
Header length: 20 bytes
Differentiated Services Field: 0x00 (DSCP 0x00: Default; ECN: 0x00)
Total Length: 48
Identification: 0xd4bd (54461)
Flags: 0x04 (Don't Fragment)
Fragment offset: 0
Time to live: 128
Protocol: TCP (0x06)
Header checksum: 0x8c0c (correct)
Source: 192.168.1.22 (192.168.1.22)
Destination: 166.67.49.252 (166.67.49.252)
Transmission Control Protocol, Src Port: smtp (25), Dst Port: 54005
(54005), Seq: 0, Ack: 1, Len: 0
Source port: smtp (25)
Destination port: 54005 (54005)
Sequence number: 0 (relative sequence number)
Acknowledgement number: 1 (relative ack number)
Header length: 28 bytes
Flags: 0x0012 (SYN, ACK)
Window size: 17520
Checksum: 0x55e9 (correct)
Options: (8 bytes)
Maximum segment size: 1460 bytes
NOP
NOP
SACK permitted

0000 00 50 f2 c9 65 a4 00 07 e9 d4 52 3c 08 00 45 00
..P..e.....R<..E.
0010 00 30 d4 bd 40 00 80 06 8c 0c c0 a8 01 16 a6 43
..0..@..........C
0020 31 fc 00 19 d2 f5 29 25 ad 86 91 cd 13 30 70 12
1.....)%.....0p.
0030 44 70 55 e9 00 00 02 04 05 b4 01 01 04 02 DpU...........

No. Time Source Destination
Protocol Info
265 32.013596 166.67.49.252 192.168.1.22 TCP
54005 > smtp [ACK] Seq=1 Ack=1 Win=65535 Len=0

Frame 265 (60 bytes on wire, 60 bytes captured)
Arrival Time: Dec 7, 2005 17:56:10.852944000
Time delta from previous packet: 0.043671000 seconds
Time since reference or first frame: 32.013596000 seconds
Frame Number: 265
Packet Length: 60 bytes
Capture Length: 60 bytes
Ethernet II, Src: 00:50:f2:c9:65:a4, Dst: 00:07:e9:d4:52:3c
Destination: 00:07:e9:d4:52:3c (Intel_d4:52:3c)
Source: 00:50:f2:c9:65:a4 (Microsof_c9:65:a4)
Type: IP (0x0800)
Trailer: 000000000000
Internet Protocol, Src Addr: 166.67.49.252 (166.67.49.252), Dst Addr:
192.168.1.22 (192.168.1.22)
Version: 4
Header length: 20 bytes
Differentiated Services Field: 0x00 (DSCP 0x00: Default; ECN: 0x00)
Total Length: 40
Identification: 0xe1ff (57855)
Flags: 0x04 (Don't Fragment)
Fragment offset: 0
Time to live: 111
Protocol: TCP (0x06)
Header checksum: 0x8fd2 (correct)
Source: 166.67.49.252 (166.67.49.252)
Destination: 192.168.1.22 (192.168.1.22)
Transmission Control Protocol, Src Port: 54005 (54005), Dst Port: smtp
(25), Seq: 1, Ack: 1, Len: 0
Source port: 54005 (54005)
Destination port: smtp (25)
Sequence number: 1 (relative sequence number)
Acknowledgement number: 1 (relative ack number)
Header length: 20 bytes
Flags: 0x0010 (ACK)
Window size: 65535
Checksum: 0xc71d (correct)
SEQ/ACK analysis
This is an ACK to the segment in frame: 264
The RTT to ACK the segment was: 0.043671000 seconds

0000 00 07 e9 d4 52 3c 00 50 f2 c9 65 a4 08 00 45 00
.....R<.P..e...E.
0010 00 28 e1 ff 40 00 6f 06 8f d2 a6 43 31 fc c0 a8
..(..@.o....C1...
0020 01 16 d2 f5 00 19 91 cd 13 30 29 25 ad 87 50 10
..........0)%..P.
0030 ff ff c7 1d 00 00 00 00 00 00 00 00 ............

And the email arrives....

Linksys router
-----------------------------------------------------------------------------------------------------

No. Time Source Destination
Protocol Info
263 13.865995 166.67.49.252 192.168.1.22 TCP
54246 > smtp [SYN] Seq=0 Ack=0 Win=65535 Len=0 MSS=1460

Frame 263 (62 bytes on wire, 62 bytes captured)
Arrival Time: Dec 7, 2005 18:32:04.404060000
Time delta from previous packet: 13.865995000 seconds
Time since reference or first frame: 13.865995000 seconds
Frame Number: 263
Packet Length: 62 bytes
Capture Length: 62 bytes
Ethernet II, Src: 00:14:bf:72:4c:aa, Dst: 00:07:e9:d4:52:3c
Destination: 00:07:e9:d4:52:3c (192.168.1.22)
Source: 00:14:bf:72:4c:aa (00:14:bf:72:4c:aa)
Type: IP (0x0800)
Internet Protocol, Src Addr: 166.67.49.252 (166.67.49.252), Dst Addr:
192.168.1.22 (192.168.1.22)
Version: 4
Header length: 20 bytes
Differentiated Services Field: 0x00 (DSCP 0x00: Default; ECN: 0x00)
Total Length: 48
Identification: 0x2fdb (12251)
Flags: 0x04 (Don't Fragment)
Fragment offset: 0
Time to live: 110
Protocol: TCP (0x06)
Header checksum: 0x42ef (correct)
Source: 166.67.49.252 (166.67.49.252)
Destination: 192.168.1.22 (192.168.1.22)
Transmission Control Protocol, Src Port: 54246 (54246), Dst Port: smtp
(25), Seq: 0, Ack: 0, Len: 0
Source port: 54246 (54246)
Destination port: smtp (25)
Sequence number: 0 (relative sequence number)
Header length: 28 bytes
Flags: 0x0002 (SYN)
Window size: 65535
Checksum: 0x1655 (correct)
Options: (8 bytes)
Maximum segment size: 1460 bytes
NOP
NOP
SACK permitted

0000 00 07 e9 d4 52 3c 00 14 bf 72 4c aa 08 00 45 00
.....R<...rL...E.
0010 00 30 2f db 40 00 6e 06 42 ef a6 43 31 fc c0 a8
..0/.@.n.B..C1...
0020 01 16 d3 e6 00 19 66 e6 97 e6 00 00 00 00 70 02
.......f.......p.
0030 ff ff 16 55 00 00 02 04 05 b4 01 01 04 02 ...U..........

No. Time Source Destination
Protocol Info
264 13.866027 192.168.1.22 166.67.49.252 TCP
smtp > 54246 [SYN, ACK] Seq=0 Ack=1 Win=17520 Len=0 MSS=1460

Frame 264 (62 bytes on wire, 62 bytes captured)
Arrival Time: Dec 7, 2005 18:32:04.404092000
Time delta from previous packet: 0.000032000 seconds
Time since reference or first frame: 13.866027000 seconds
Frame Number: 264
Packet Length: 62 bytes
Capture Length: 62 bytes
Ethernet II, Src: 00:07:e9:d4:52:3c, Dst: 00:14:bf:72:4c:aa
Destination: 00:14:bf:72:4c:aa (00:14:bf:72:4c:aa)
Source: 00:07:e9:d4:52:3c (192.168.1.22)
Type: IP (0x0800)
Internet Protocol, Src Addr: 192.168.1.22 (192.168.1.22), Dst Addr:
166.67.49.252 (166.67.49.252)
Version: 4
Header length: 20 bytes
Differentiated Services Field: 0x00 (DSCP 0x00: Default; ECN: 0x00)
Total Length: 48
Identification: 0x098f (2447)
Flags: 0x04 (Don't Fragment)
Fragment offset: 0
Time to live: 128
Protocol: TCP (0x06)
Header checksum: 0x573b (correct)
Source: 192.168.1.22 (192.168.1.22)
Destination: 166.67.49.252 (166.67.49.252)
Transmission Control Protocol, Src Port: smtp (25), Dst Port: 54246
(54246), Seq: 0, Ack: 1, Len: 0
Source port: smtp (25)
Destination port: 54246 (54246)
Sequence number: 0 (relative sequence number)
Acknowledgement number: 1 (relative ack number)
Header length: 28 bytes
Flags: 0x0012 (SYN, ACK)
Window size: 17520
Checksum: 0x1885 (correct)
Options: (8 bytes)
Maximum segment size: 1460 bytes
NOP
NOP
SACK permitted
SEQ/ACK analysis
This is an ACK to the segment in frame: 263
The RTT to ACK the segment was: 0.000032000 seconds

0000 00 14 bf 72 4c aa 00 07 e9 d4 52 3c 08 00 45 00
....rL.....R<..E.
0010 00 30 09 8f 40 00 80 06 57 3b c0 a8 01 16 a6 43
..0..@...W;.....C
0020 31 fc 00 19 d3 e6 08 72 b0 dc 66 e6 97 e7 70 12
1......r..f...p.
0030 44 70 18 85 00 00 02 04 05 b4 01 01 04 02 Dp............

No. Time Source Destination
Protocol Info
265 13.909749 166.67.49.252 192.168.1.22 TCP
54246 > smtp [ACK] Seq=1 Ack=1 Win=65535 [CHECKSUM INCORRECT] Len=0

Frame 265 (60 bytes on wire, 60 bytes captured)
Arrival Time: Dec 7, 2005 18:32:04.447814000
Time delta from previous packet: 0.043722000 seconds
Time since reference or first frame: 13.909749000 seconds
Frame Number: 265
Packet Length: 60 bytes
Capture Length: 60 bytes
Ethernet II, Src: 00:14:bf:72:4c:aa, Dst: 00:07:e9:d4:52:3c
Destination: 00:07:e9:d4:52:3c (192.168.1.22)
Source: 00:14:bf:72:4c:aa (00:14:bf:72:4c:aa)
Type: IP (0x0800)
Trailer: 0000BDC33A70
Internet Protocol, Src Addr: 166.67.49.252 (166.67.49.252), Dst Addr:
192.168.1.22 (192.168.1.22)
Version: 4
Header length: 20 bytes
Differentiated Services Field: 0x00 (DSCP 0x00: Default; ECN: 0x00)
Total Length: 40
Identification: 0x2fdc (12252)
Flags: 0x04 (Don't Fragment)
Fragment offset: 0
Time to live: 111
Protocol: TCP (0x06)
Header checksum: 0x41f6 (correct)
Source: 166.67.49.252 (166.67.49.252)
Destination: 192.168.1.22 (192.168.1.22)
Transmission Control Protocol, Src Port: 54246 (54246), Dst Port: smtp
(25), Seq: 1, Ack: 1, Len: 0
Source port: 54246 (54246)
Destination port: smtp (25)
Sequence number: 1 (relative sequence number)
Acknowledgement number: 1 (relative ack number)
Header length: 20 bytes
Flags: 0x0010 (ACK)
Window size: 65535
Checksum: 0xa8aa (incorrect, should be 0x89b9)
SEQ/ACK analysis
This is an ACK to the segment in frame: 264
The RTT to ACK the segment was: 0.043722000 seconds

0000 00 07 e9 d4 52 3c 00 14 bf 72 4c aa 08 00 45 00
.....R<...rL...E.
0010 00 28 2f dc 40 00 6f 06 41 f6 a6 43 31 fc c0 a8
..(/.@.o.A..C1...
0020 01 16 d3 e6 00 19 66 e6 97 e7 08 72 b0 dd 50 10
.......f....r..P.
0030 ff ff a8 aa 00 00 00 00 bd c3 3a 70 ..........

No. Time Source Destination
Protocol Info
269 17.062671 192.168.1.22 166.67.49.252 TCP
smtp > 54246 [SYN, ACK] Seq=0 Ack=1 Win=17520 Len=0 MSS=1460

Frame 269 (62 bytes on wire, 62 bytes captured)
Arrival Time: Dec 7, 2005 18:32:07.600736000
Time delta from previous packet: 3.152922000 seconds
Time since reference or first frame: 17.062671000 seconds
Frame Number: 269
Packet Length: 62 bytes
Capture Length: 62 bytes
Ethernet II, Src: 00:07:e9:d4:52:3c, Dst: 00:14:bf:72:4c:aa
Destination: 00:14:bf:72:4c:aa (00:14:bf:72:4c:aa)
Source: 00:07:e9:d4:52:3c (192.168.1.22)
Type: IP (0x0800)
Internet Protocol, Src Addr: 192.168.1.22 (192.168.1.22), Dst Addr:
166.67.49.252 (166.67.49.252)
Version: 4
Header length: 20 bytes
Differentiated Services Field: 0x00 (DSCP 0x00: Default; ECN: 0x00)
Total Length: 48
Identification: 0x09ae (2478)
Flags: 0x04 (Don't Fragment)
Fragment offset: 0
Time to live: 128
Protocol: TCP (0x06)
Header checksum: 0x571c (correct)
Source: 192.168.1.22 (192.168.1.22)
Destination: 166.67.49.252 (166.67.49.252)
Transmission Control Protocol, Src Port: smtp (25), Dst Port: 54246
(54246), Seq: 0, Ack: 1, Len: 0
Source port: smtp (25)
Destination port: 54246 (54246)
Sequence number: 0 (relative sequence number)
Acknowledgement number: 1 (relative ack number)
Header length: 28 bytes
Flags: 0x0012 (SYN, ACK)
Window size: 17520
Checksum: 0x1885 (correct)
Options: (8 bytes)
Maximum segment size: 1460 bytes
NOP
NOP
SACK permitted

0000 00 14 bf 72 4c aa 00 07 e9 d4 52 3c 08 00 45 00
....rL.....R<..E.
0010 00 30 09 ae 40 00 80 06 57 1c c0 a8 01 16 a6 43
..0..@...W......C
0020 31 fc 00 19 d3 e6 08 72 b0 dc 66 e6 97 e7 70 12
1......r..f...p.
0030 44 70 18 85 00 00 02 04 05 b4 01 01 04 02 Dp............

No. Time Source Destination
Protocol Info
357 23.624735 192.168.1.22 166.67.49.252 TCP
smtp > 54246 [SYN, ACK] Seq=0 Ack=1 Win=17520 Len=0 MSS=1460

Frame 357 (62 bytes on wire, 62 bytes captured)
Arrival Time: Dec 7, 2005 18:32:14.162800000
Time delta from previous packet: 6.562064000 seconds
Time since reference or first frame: 23.624735000 seconds
Frame Number: 357
Packet Length: 62 bytes
Capture Length: 62 bytes
Ethernet II, Src: 00:07:e9:d4:52:3c, Dst: 00:14:bf:72:4c:aa
Destination: 00:14:bf:72:4c:aa (00:14:bf:72:4c:aa)
Source: 00:07:e9:d4:52:3c (192.168.1.22)
Type: IP (0x0800)
Internet Protocol, Src Addr: 192.168.1.22 (192.168.1.22), Dst Addr:
166.67.49.252 (166.67.49.252)
Version: 4
Header length: 20 bytes
Differentiated Services Field: 0x00 (DSCP 0x00: Default; ECN: 0x00)
Total Length: 48
Identification: 0x0a31 (2609)
Flags: 0x04 (Don't Fragment)
Fragment offset: 0
Time to live: 128
Protocol: TCP (0x06)
Header checksum: 0x5699 (correct)
Source: 192.168.1.22 (192.168.1.22)
Destination: 166.67.49.252 (166.67.49.252)
Transmission Control Protocol, Src Port: smtp (25), Dst Port: 54246
(54246), Seq: 0, Ack: 1, Len: 0
Source port: smtp (25)
Destination port: 54246 (54246)
Sequence number: 0 (relative sequence number)
Acknowledgement number: 1 (relative ack number)
Header length: 28 bytes
Flags: 0x0012 (SYN, ACK)
Window size: 17520
Checksum: 0x1885 (correct)
Options: (8 bytes)
Maximum segment size: 1460 bytes
NOP
NOP
SACK permitted

0000 00 14 bf 72 4c aa 00 07 e9 d4 52 3c 08 00 45 00
....rL.....R<..E.
0010 00 30 0a 31 40 00 80 06 56 99 c0 a8 01 16 a6 43
..0.1@...V......C
0020 31 fc 00 19 d3 e6 08 72 b0 dc 66 e6 97 e7 70 12
1......r..f...p.
0030 44 70 18 85 00 00 02 04 05 b4 01 01 04 02 Dp............

No more packets....