sendmail on Solaris 8 brings down MS Exchange servers - is this possible?

sendmail on Solaris 8 brings down MS Exchange servers - is this possible?

Post by Hank Kingsle » Wed, 05 Jun 2002 21:53:18



I have a Sun Server plugged into my clients corporate network.  It's running
Solaris 8 and a network management application.  Sometime ago my clients'
Microsoft Exchange servers went down.  Broadcast packets were traced back to
my Sun server.  When my server was disconnected from the network the
Exchange servers came back up.

My Solaris 8 install has not had sendmail changed in anyway.  The sendmail
config file has not been changed from default.  There are a few sendmail
warinings in the /var/adm/messages file though.

Can sendmail bring down MS Exchange servers?

 
 
 

sendmail on Solaris 8 brings down MS Exchange servers - is this possible?

Post by Dennis Clark » Thu, 06 Jun 2002 00:43:08





>>I have a Sun Server plugged into my clients corporate network.  It's running
>>Solaris 8 and a network management application.  Sometime ago my clients'
>>Microsoft Exchange servers went down.  Broadcast packets were traced back to
>>my Sun server.  When my server was disconnected from the network the
>>Exchange servers came back up.

>>My Solaris 8 install has not had sendmail changed in anyway.  The sendmail
>>config file has not been changed from default.  There are a few sendmail
>>warinings in the /var/adm/messages file though.

>>Can sendmail bring down MS Exchange servers?

> From what I've heard about M$ "enterprise" solutions, I wouldn't be
> surprised.  I'll bet the people that pointed the finger where the M$ IT
> folks, right?

I have a client that recently added a V880 on their server backbone running
GigaBit ethernet.  They have three MS Exchange servers that were crashing on a
more or less regular basis.  After the addition of the V880 these MS Exchange
servers began to crash on a more or less regular basis.  We took the V880 off
the network for a while and the MS Exchange servers went back to crashing on a
more or less regular basis.  The MS folks were incensed at the Sun server for
causing this problem even before we installed it in the server room and now
are claiming that an MS Exchange server can predict when you are going to
switch to a more stable platform and will punish its users with downtime for
even thinking about the concept.  Perhaps the MS Exchange server can read into
the content of the purchasing departments emails and see that a V880 was being
bought?  Truely advanced technology.

Dennis Clarke

 
 
 

sendmail on Solaris 8 brings down MS Exchange servers - is this possible?

Post by Alan Coopersmi » Thu, 06 Jun 2002 01:51:06



|Can sendmail bring down MS Exchange servers?

Simply asking them to deliver mail can bring down MS Exchange servers:
http://techupdate.zdnet.com/techupdate/stories/main/0,14179,2868464,0...

--
________________________________________________________________________


  Working for, but definitely not speaking for, Sun Microsystems, Inc.

 
 
 

sendmail on Solaris 8 brings down MS Exchange servers - is this possible?

Post by Hank Kingsle » Thu, 06 Jun 2002 02:07:52


Cheers Dennis, does any of this relate to sendmail though?  What was the
solution to the problem in the end?  What was running on VX880?





> >>I have a Sun Server plugged into my clients corporate network.  It's
running
> >>Solaris 8 and a network management application.  Sometime ago my
clients'
> >>Microsoft Exchange servers went down.  Broadcast packets were traced
back to
> >>my Sun server.  When my server was disconnected from the network the
> >>Exchange servers came back up.

> >>My Solaris 8 install has not had sendmail changed in anyway.  The
sendmail
> >>config file has not been changed from default.  There are a few sendmail
> >>warinings in the /var/adm/messages file though.

> >>Can sendmail bring down MS Exchange servers?

> > From what I've heard about M$ "enterprise" solutions, I wouldn't be
> > surprised.  I'll bet the people that pointed the finger where the M$ IT
> > folks, right?

> I have a client that recently added a V880 on their server backbone
running
> GigaBit ethernet.  They have three MS Exchange servers that were crashing
on a
> more or less regular basis.  After the addition of the V880 these MS
Exchange
> servers began to crash on a more or less regular basis.  We took the V880
off
> the network for a while and the MS Exchange servers went back to crashing
on a
> more or less regular basis.  The MS folks were incensed at the Sun server
for
> causing this problem even before we installed it in the server room and
now
> are claiming that an MS Exchange server can predict when you are going to
> switch to a more stable platform and will punish its users with downtime
for
> even thinking about the concept.  Perhaps the MS Exchange server can read
into
> the content of the purchasing departments emails and see that a V880 was
being
> bought?  Truely advanced technology.

> Dennis Clarke

 
 
 

sendmail on Solaris 8 brings down MS Exchange servers - is this possible?

Post by Hank Kingsle » Thu, 06 Jun 2002 03:06:19


Cheers Alan, i'll check what version of Exchange their IT department have
and see if it's patched.  I take it sendmail uses RFC 821 and 822 SMTP
messages.  Hopefully this is a quick end to what could turn into a long
running problem for me!



> |Can sendmail bring down MS Exchange servers?

> Simply asking them to deliver mail can bring down MS Exchange servers:

http://techupdate.zdnet.com/techupdate/stories/main/0,14179,2868464,0...

> --
> ________________________________________________________________________


>   Working for, but definitely not speaking for, Sun Microsystems, Inc.

 
 
 

sendmail on Solaris 8 brings down MS Exchange servers - is this possible?

Post by Thomas H Jones I » Thu, 06 Jun 2002 08:25:49




>Cheers Dennis, does any of this relate to sendmail though?  What was the
>solution to the problem in the end?  What was running on VX880?



>> Perhaps the MS Exchange server can read into the content of the
>> purchasing departments emails and see that a V880 was being bought?
>> Truely advanced technology.

just a guess, but I think Dennis's reply was a joke. What's more, I
would hazzard that his joke's point was that the sendmail process would
not cause the MicroSoft systems to crash.

-tom
--

"You can only be -so- accurate with a claw-hammer."  --me

 
 
 

sendmail on Solaris 8 brings down MS Exchange servers - is this possible?

Post by Andrew Gabri » Thu, 06 Jun 2002 08:39:12




Quote:> I have a Sun Server plugged into my clients corporate network.  It's running
> Solaris 8 and a network management application.  Sometime ago my clients'
> Microsoft Exchange servers went down.  Broadcast packets were traced back to
> my Sun server.

What were the packets?

Quote:> When my server was disconnected from the network the
> Exchange servers came back up.

> My Solaris 8 install has not had sendmail changed in anyway.  The sendmail
> config file has not been changed from default.  There are a few sendmail
> warinings in the /var/adm/messages file though.

> Can sendmail bring down MS Exchange servers?

No, and neither does sendmail send any broadcast packets directly,
although it might cause things like resolvers to do so.

--
Andrew Gabriel
Consultant Software Engineer

 
 
 

sendmail on Solaris 8 brings down MS Exchange servers - is this possible?

Post by Chris Watkin » Thu, 06 Jun 2002 08:59:23



> Cheers Dennis, does any of this relate to sendmail though?  What was the
> solution to the problem in the end?  What was running on VX880?

Sendmail running on a unix box will not, in and of itself, cause some
windoze *to break, somewhere else. That's pure logic.

That said... there are *many* Exchange exploits, holes, bugs, etc...
that someone *using* sendmail could use to bring down the Exchange
server. It could even be a cron'd job, that's sending out an email
with headers that the Exchange server croaks on.
In *my* opinion, that's still a windows problem, not a unix problem.
Sure, if that's the case, then killing the sendmail cures their problem.
That's not the way it's supposed to work, though.

Anything running on a Unix box is, simply put, filed into a fishbowl
of exuses, and the windows freaks pull one out of the bowl every
time something crashes or breaks.

Apparently, this is the global Windows admin solution:
Blame the Unix group.

No offense meant to the responsible and knowledgeable Windows
admins out there in the IT world...  all three of you.

Chris
--
 Remove the spamhole to reply.

 
 
 

sendmail on Solaris 8 brings down MS Exchange servers - is this possible?

Post by cjt » Thu, 06 Jun 2002 09:28:05



> I have a Sun Server plugged into my clients corporate network.  It's running
> Solaris 8 and a network management application.  Sometime ago my clients'
> Microsoft Exchange servers went down.  Broadcast packets were traced back to
> my Sun server.  When my server was disconnected from the network the
> Exchange servers came back up.

> My Solaris 8 install has not had sendmail changed in anyway.  The sendmail
> config file has not been changed from default.  There are a few sendmail
> warinings in the /var/adm/messages file though.

> Can sendmail bring down MS Exchange servers?

I thought a hint of rain within a hundred miles could bring them down. <g>
 
 
 

sendmail on Solaris 8 brings down MS Exchange servers - is this possible?

Post by Rich Tee » Thu, 06 Jun 2002 09:39:54



> Apparently, this is the global Windows admin solution:
> Blame the Unix group.

Is that before or after rebooting the server?

--
Rich Teer

President,
Rite Online Inc.

Voice: +1 (250) 979-1638
URL: http://www.rite-online.net

 
 
 

sendmail on Solaris 8 brings down MS Exchange servers - is this possible?

Post by Stuart Lamb » Thu, 06 Jun 2002 09:44:00





>> Apparently, this is the global Windows admin solution:
>> Blame the Unix group.

>Is that before or after rebooting the server?

At the same time. After all, the Windows admin needs _something_ to do
whilst waiting for the server to come back up...

--
I'm waiting for tech support to call me back. I'm also waiting for the
second coming of Jesus. Wanna take bets on which happens first?

 
 
 

sendmail on Solaris 8 brings down MS Exchange servers - is this possible?

Post by Andrzej Fili » Fri, 07 Jun 2002 00:55:00



> I have a Sun Server plugged into my clients corporate network.  It's running
> Solaris 8 and a network management application.  Sometime ago my clients'
> Microsoft Exchange servers went down.  Broadcast packets were traced back to
> my Sun server.  When my server was disconnected from the network the
> Exchange servers came back up.

What exatly has been discovered ?

Quote:> My Solaris 8 install has not had sendmail changed in anyway.  The sendmail
> config file has not been changed from default.  There are a few sendmail
> warinings in the /var/adm/messages file though.

Can you post the warnings ?

Quote:> Can sendmail bring down MS Exchange servers ?

--

366A 5DD7 7707 379C 9251  32AE C948 0BD2 7D99 688A  expires: 2003-01-25
I may disagree with the following *random epigram* :
To use * is to already be defeated.
                -- Chinese proverb
 
 
 

sendmail on Solaris 8 brings down MS Exchange servers - is this possible?

Post by Andrew 'Ender' Wiggi » Fri, 07 Jun 2002 05:01:06




>>Apparently, this is the global Windows admin solution:
>>Blame the Unix group.

> Is that before or after rebooting the server?

Hey, those boxes reboot themselves, no need for them to do that extra
work...

Ender

Quote:> --
> Rich Teer

> President,
> Rite Online Inc.

> Voice: +1 (250) 979-1638
> URL: http://www.rite-online.net

 
 
 

sendmail on Solaris 8 brings down MS Exchange servers - is this possible?

Post by Hank Kingsle » Fri, 07 Jun 2002 06:56:54


Problem solved.  The Exchange servers were shut down deliberately because
HTTP requests were being sent on port 80 (of course!) to a number of
unidentified servers from my Unix server.  The IT department didn't want to
risk another Nimda type virus, that exploits MS IIS, and therefore turned
their servers off  to prevent an Outlook flood or something.


Quote:> I have a Sun Server plugged into my clients corporate network.  It's
running
> Solaris 8 and a network management application.  Sometime ago my clients'
> Microsoft Exchange servers went down.  Broadcast packets were traced back
to
> my Sun server.  When my server was disconnected from the network the
> Exchange servers came back up.

> My Solaris 8 install has not had sendmail changed in anyway.  The sendmail
> config file has not been changed from default.  There are a few sendmail
> warinings in the /var/adm/messages file though.

> Can sendmail bring down MS Exchange servers?

 
 
 

sendmail on Solaris 8 brings down MS Exchange servers - is this possible?

Post by Hank Kingsle » Fri, 07 Jun 2002 06:58:37


Fixed.  There was no problem with sendmail.  It was an over cautious IT dept
shutting down their Exchange servers.  See my post in comp.unix.solaris.



> > I have a Sun Server plugged into my clients corporate network.  It's
running
> > Solaris 8 and a network management application.  Sometime ago my
clients'
> > Microsoft Exchange servers went down.  Broadcast packets were traced
back to
> > my Sun server.  When my server was disconnected from the network the
> > Exchange servers came back up.

> What exatly has been discovered ?

> > My Solaris 8 install has not had sendmail changed in anyway.  The
sendmail
> > config file has not been changed from default.  There are a few sendmail
> > warinings in the /var/adm/messages file though.

> Can you post the warnings ?

> > Can sendmail bring down MS Exchange servers ?

> --

> 366A 5DD7 7707 379C 9251  32AE C948 0BD2 7D99 688A  expires: 2003-01-25
> I may disagree with the following *random epigram* :
> To use * is to already be defeated.
> -- Chinese proverb

 
 
 

1. Linux Firewalls, MS Proxy Server and MS Exchange Server

Hi all,

I will be modifying a LAN config in the near future and was looking for any
thoughts, mods, etc. for what I have in mind. Feel free to shoot it down in
flames - but do it nicely :-)

Currently, the set up is a single subnet, with a multi-homed box hosting
both MS Proxy Server and MS Exchange Server. This is linked to a
dial-on-demand ISDN router via the extrernal network card. All very
simple....

In a few months we'll be going over to an ASDL line, fixed IP address (or
range) and I want to secure the network appropriately. We may also want to
host our own web and ftp servers at a later date.

I've been looking through the newgroups and FAQ sites and a suitable set up
seems to be:

ASDL router
|
|
|
Linux Firewall -----------Future DMZ segment for Web and FTP servers
|
|
|
 Secured LAN with MS Exchange Server and MS Proxy Server

The firewall will be providing MASQuarading for the LAN - together with
packet filtering.
Any future web and ftp servers would be implemented with a seperate DMZ
network segment off of a third NIC on the firewall.

The following config is what I'm not too sure about....

In order to log web access and provide caching, we will keep the proxy
server on the internal LAN - but it will not be the firewall, just a regular
node with the linux firewall set as its gateway. Generally, all outbound
web, ftp etc access will be blocked except for the appropriate proxy server
ports and IP address. Then any MS client needing internet access will use
the proxy sever via winsock etc. Any future non-MS boxes could access
through the firewall directly - having set up specific outbound rules for
their IP addresses on the firewall.

The MS Exchange server will be placed on the internal LAN - not the DNZ. The
SMTP feed will be routed through the firewall. ##### Does anyone have any
insights on setting up such a rule for IPCHAINS - can it be done when the
firewall is MASQuarading the rest of the LAN?

There would also be an internal DNS server handling cache forwarding to the
DNS servers of the ISP. This would be placed on the internal LAN.

Any suggestions, ideas, flames etc more than welcome.

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