sendmail question?

sendmail question?

[arslan saeed]

Hi,

We are running sendmail on redhat linux 7.3. When internet connectivity goes
down at times, local users get smtp time-out messages (server not
responding). I figured the cause of this message is that by default sendmail
does initial dns lookups on all messages it recieves and in case of internet
connectivity being down, it is not able to do so and produces this message.

so I configured sendmail in defered delivery mode so that it should queue
every message and should  not do dns lookups and accept emails from local
users in case of internet connectivity being down.

However I figured that in defered delivery mode it does not implement anti
spam configuration in access map. When I change delivery mode to defaulot
background or queue-only then it looks access maps and prevents mail
spamming.

Is there anyway to make access maps work in deferred delivery mode. or any
other configuration in which sendmail implements anti spam rules and also
does not do initial dns maps so that email could be queued by sendmail even
when it cannot reach internet.

thanks
arslan.

Re: sendmail question?

[Jeff Largent]

2 servers, one inside firewall that local users use, one outside firewall
or on dmz that accepts connections from the outside.

arslan saeed wrote:
> Hi,
> 
> We are running sendmail on redhat linux 7.3. When internet connectivity goes
> down at times, local users get smtp time-out messages (server not
> responding). I figured the cause of this message is that by default sendmail
> does initial dns lookups on all messages it recieves and in case of internet
> connectivity being down, it is not able to do so and produces this message.
> 
> so I configured sendmail in defered delivery mode so that it should queue
> every message and should  not do dns lookups and accept emails from local
> users in case of internet connectivity being down.
> 
> However I figured that in defered delivery mode it does not implement anti
> spam configuration in access map. When I change delivery mode to defaulot
> background or queue-only then it looks access maps and prevents mail
> spamming.
> 
> Is there anyway to make access maps work in deferred delivery mode. or any
> other configuration in which sendmail implements anti spam rules and also
> does not do initial dns maps so that email could be queued by sendmail even
> when it cannot reach internet.
> 
> thanks
> arslan.
> 
> -
> To unsubscribe from this list: send the line "unsubscribe linux-admin" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 
> 

-- 
Jeff Largent                   ImageLinks, Inc.
Sr System Admin                Melbourne, Fl 32935
(321) 253-0011                 fax: (321) 253-5559

Re: sendmail question?

[Ben Clewett]

Another option is to use two copies of Sendmail bound to differenet IP 
addresses, as is now possible.  Each use different sendmail.cf, which 
will not conflict.  Works well for me :)

I advise using /etc/mail_int for all the .cf, .mc, .m4, alias and 
virt-user tables, and /etc/mail_ext for the same on the external.

If your having problems with DNS, install a caching name sever (named) 
and edit /etc/resolve.conf to point to 127.0.0.1.  This can help.  But 
really sendmail and dns are very closelly tied together, and sendmail 
uses dns for a lot of activity.  From validating recipient, validating 
email, checking for a valid MX for the destination host...  Trying to 
run sendmail without dns is simply not a good idea. :)

Best of luck.  PS, the news group comp.mail.sendmail is a better place 
for good feedback.

Ben Clewett.

Jeff Largent wrote:
> 2 servers, one inside firewall that local users use, one outside firewall
> or on dmz that accepts connections from the outside.
> 
> arslan saeed wrote:
> 
>> Hi,
>>
>> We are running sendmail on redhat linux 7.3. When internet 
>> connectivity goes
>> down at times, local users get smtp time-out messages (server not
>> responding). I figured the cause of this message is that by default 
>> sendmail
>> does initial dns lookups on all messages it recieves and in case of 
>> internet
>> connectivity being down, it is not able to do so and produces this 
>> message.
>>
>> so I configured sendmail in defered delivery mode so that it should queue
>> every message and should  not do dns lookups and accept emails from local
>> users in case of internet connectivity being down.
>>
>> However I figured that in defered delivery mode it does not implement 
>> anti
>> spam configuration in access map. When I change delivery mode to defaulot
>> background or queue-only then it looks access maps and prevents mail
>> spamming.
>>
>> Is there anyway to make access maps work in deferred delivery mode. or 
>> any
>> other configuration in which sendmail implements anti spam rules and also
>> does not do initial dns maps so that email could be queued by sendmail 
>> even
>> when it cannot reach internet.
>>
>> thanks
>> arslan.
>>
>> -
>> To unsubscribe from this list: send the line "unsubscribe linux-admin" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>>
>>
>