Um 21:33 Uhr am 17.02.06 schrieb Jürgen Herz:
> Sven Hartge wrote:

>>> Exim advertises STARTTLS in the EHLO response but upon sending the 
>>> STARTTLS command, nothing happens, it looks some client input is 
>>> expected. Not if connected via client nor by hand (telnet).
 
>> You should see a "220 TLS go ahead" if you use telnet to debug.
>> 
>> My guess: Your server is out of entropy (check 
>> /proc/sys/kernel/random/entropy_avail, it should be >2000) and exim is 
>> still calculating its dh_params and session key.
 
> Yesterday before posting I already read a hint on the web regarding 
> entropy_avail. When I checked this, it was 5 - but I thought it's ok 
> since it's not null.

This means "5 bits of entropy left". gnutls uses vast amounts of entropy 
(compared to openssl), so it drains the entropy pool very quick.

> Yesterday, long after I mailed my post, I finally noticed errors on the 
> TLS connections showing up in the logs (about 3 hours after telnetting 
> and killing telnet after waiting a few minutes for response).
> 
> Today I just tested STARTTLS again and instantly got the expected 220. 
> And indeed, today entropy_vail was 1184 when started. But this value is 
> quite inconsistent and mostly is around 5.

exim-4.50 has a little "bug" in its gnutls-code, which causes it to use 
the blocking /dev/random on SSL connections. Florian Weimer made a patch, 
which resolves this issue for 4.50.

If you can, upgrade to at least 4.54, better yet 4.60.

If you use Debian, use the packages from backports.org.

> Now I'm quite puzzled, but after some searches it looks like a common
> problem. ldd says exim4 is linked against libgnutls.so.11 as well as
> libssl.so.0.9.7. Does this mean I can choose at runtime which lib to use?

This is weird. Please post your ldd output.

S°

-- 
Sven Hartge -- professioneller Unix-Geek
Meine Gedanken im Netz: http://www.svenhartge.de/

Achtung, neue Mail-Adresse: [EMAIL PROTECTED]

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