[CentOS] Sendmail - STARTTLS not appear on one client

Radu Radutiu rradutiu at gmail.com
Mon Dec 1 06:54:14 UTC 2008

On Fri, Nov 28, 2008 at 11:30 PM, happymaster23 <happymaster23 at gmail.com> wrote:
> Hi,
> I have Sendmail configured to use STARTTLS for authentication. On all
> internet connections and computers (that I have tested) works
> connection over encrypted SMTP flawlessly. Today I was setting up mail
> client on PC of my customer and standardily checked boxes, that I want
> to use SSL for POP3 and SMTP. Next I wanted to check configuration (by
> sending email from this mailbox to this mailbox) but it does not work.
> So I have opened telnet, connected via port 25 and writed "ehlo
> hostname" and then finded out, that there is missing STARTTLS. Is
> possible, that some bad configuration on client side (firewall,
> etc...) can cause this error including that this function is missing
> in printout of ehlo? POP3S working good.


I have seen this kind of problem (STARTTLS not available for a single
client but working for everyone else) when the client is behind a
CISCO firewall with the FIXUP SMTP configuration option enabled.
Disable it using "no fixup protocol smtp 25" on the firewall and try



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