Re: [exim] Ports

On Mon, Aug 16, 2010 at 5:34 PM, David Woodhouse <dwmw2@???> wrote:
> On Mon, 2010-08-16 at 17:32 -0700, Brent Jones wrote:
>> Shouldnt need any ICMP ports open inbound for SMTP, its all TCP.
>
> There's no such thing as 'ICMP ports'.
>
> TCP doesn't work if ICMP is blocked.
>
> --
> dwmw2
>
>

I guess I should clarify, ICMP 'types'. :)

I've seen rare situations where PMTUD breaks past a firewall that
blocks all ICMP types. But I've tested with all ICMP blocked and only
under certain situations where the remote side found an odd MTU would
it break. But it could very well likely happen more often than that in
the wild.

--
Brent Jones
brent@???