Re: reality check: passive FTP
On Tuesday 29 August 2006 11:36, Andrew Miehs wrote:
> Is this for real?! Or did you just want to send us a funny mail?
>
> > 23.311491 local -> remote TCP 38486 > 1455 [SYN] Seq=0 Ack=0
> > Win=5840 Len=0 MSS=1460 TSV=4672689 TSER=0 WS=7
>
> Whats up with this? Looks like local has a broken ftp client, or why
> is it trying to make a non passive connection?!
IIRC, that's a passive connection to the port (5*256+175) specified
in the preceding 227 response. Regular/active FTP works by having
the server open a connection back to the client.
Looks like a firewall problem to me. The question is where. The
repeated SYNs suggest that the disputed packets are being dropped
rather than ICMP rejected. Is there a TCP equivalent to tracepath?
--Mike Bird
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