[Dovecot] No localhost after reboot

[Matthias Andree]

"Bob Hall" <rjhjr at cox.net> writes:

>> SYN_SENT shouldn't happen for loopback connections.
>
> Hmm. How are you going to establish a TCP connection without a
> handshake? 

Of course, SYN_SENT will be one state, but I find it intimidating that
apparently all other services work but one on the same interface. There
isn't really much that the application can do to prevent the kernel from
returning ACK.

Are you running a firewall? Check its stats to see where the packets are
lost. Are you running BPF-based applications? Might one of these
hijack^Wdetour the packets?

> The interface doesn't make any difference. Besides, it has nothing to do 
> with Dovecot. Dovecot is the intended recipient, not the sender.

Shouldn't matter, the connection is bidirectional, but the
SYN|ACK-packet is not getting returned -- and on lo0, it's kernel
replying to itself, so it must work unless something is in the way.

Can you tcpdump port 143 on lo (or lo0)?
Can you strace/truss/whichever the process listening on localhost's port
143 to see if it shows any other signs of life?

-- 
Matthias Andree

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