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[VLAN] telnet to vlan device fails

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Hi list,

I've discovered a strange problem.  I've got two hosts with tagged interfaces called eth0.5.
When I try to telnet from host1 to host2 the session hangs where it should print out "Login:".  I
have no problems pinging host2 from host1 - even if I use max payload frames!

I've run tcpdump -i eth0.5 on host1 when trying to telnet to host2, and I've copied the output to
the end of this email.  It would seem that host2 (192.168.5.254) responds okay to the initial SYN
with a SYN/ACK.  host1 (192.168.5.1) then sends some data and host2 then correctly ACKs this. 
But then host2 starts sending packets which have the first 10 bytes stripped!

I don't know why host2 is sending these packets.  However, it *is* running old software
(linux-2.4.4) and I have found that if I replace it with a host running later software
(linux-2.4.25) and create eth0.5 on this new host, then I have no problem telnetting into it.

Is this a known problem?

Alex


-----------------------------
# tcpdump -i eth0.5 


15:31:12.625957 192.168.5.1.32794 > 192.168.5.254.telnet: S 1908700301:1908700301(0) win 5840 <mss
1460,sackOK,timestamp 102094 0,nop,wscale 0> (DF) [tos 0x10] 15:31:12.626886 192.168.5.254.telnet >
192.168.5.1.32794: S 3836006744:3836006744(0) ack 1908700302 win 5792 <mss 1460,sackOK,timestamp
368921 102094,nop,wscale 0> (DF) 15:31:12.626943 192.168.5.1.32794 > 192.168.5.254.telnet: . ack 1
win 5840 <nop,nop,timestamp 102094 368921> (DF) [tos 0x10] 15:31:12.632113 192.168.5.1.32794 >
192.168.5.254.telnet: P 1:34(33) ack 1 win 5840 <nop,nop,timestamp 102095 368921> (DF) [tos 0x10]
15:31:12.632738 192.168.5.254.telnet > 192.168.5.1.32794: . ack 34 win 5792 <nop,nop,timestamp
368922 102095> (DF) 15:31:12.935233 0:40:70:44:40:0 0:e9:8:0:45:10 4006 78:
                         3e14 c0a8 05fe c0a8 0501 0017 801a e4a4
                         d159 71c4 74af 8018 16a0 4fc4 0000 0101
                         080a 0005 a138 0001 8ecf fffd 18ff fd20
                         fffd 23ff fd27 0100 0000 0000 0000 0100
15:31:13.136972 0:40:70:45:40:0 0:e9:8:0:45:10 4006 78:
                         3e13 c0a8 05fe c0a8 0501 0017 801a e4a4
                         d159 71c4 74af 8018 16a0 4faf 0000 0101
                         080a 0005 a14d 0001 8ecf fffd 18ff fd20
                         fffd 23ff fd27 2031 3932 2e31 3638 2e35
15:31:13.556987 0:40:70:46:40:0 0:e9:8:0:45:10 4006 78:
                         3e12 c0a8 05fe c0a8 0501 0017 801a e4a4
                         d159 71c4 74af 8018 16a0 4f85 0000 0101
                         080a 0005 a177 0001 8ecf fffd 18ff fd20
                         fffd 23ff fd27 0083 4000 0202 0000 8340
15:31:14.397031 0:40:70:47:40:0 0:e9:8:0:45:10 4006 78:
                         3e11 c0a8 05fe c0a8 0501 0017 801a e4a4
                         d159 71c4 74af 8018 16a0 4f31 0000 0101
                         080a 0005 a1cb 0001 8ecf fffd 18ff fd20
                         fffd 23ff fd27 00f9 0305 00fd 0303 00ff

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