Sendmail (8.11.0)Problem on HPUX 11.00

[roobala]

Hi,

We have Sendmail 8.11 running on HPUX 11.00,
System is working well,


In mailq, lot of mails are there with the following errors.
"(host map: lookup (DOMAIN NAME): deferred)" .


Example ::

f955inw25419 4966 Fri Oct 5 11:14
(host map: lookup (bom3.vsnl.net.in): deferred)



Similarly mailq is there for so many domains.
In general mails are going to all domains.

-----------------------------------------------

when we try to send mail by command mode error is like this:

Mail1 # sendmail -v midas@bom3.vsnl.net.in
midas@bom3.vsnl.net.in... bom3.vsnl.net.in: Name server timeout
midas@bom3.vsnl.net.in... Transient parse error -- message queued for future del
ivery
Test Mail Pls.ignore
.
midas@bom3.vsnl.net.in... queued

-----------------------------------------------
Error says name server timed out,
But the DNS Query for the same domain is working well

Mail1 # nslookup
Default Name Server: dns1.bplnet.com
Address: 202.169.129.40

> bom3.vsnl.net.in
Name Server: dns1.bplnet.com
Address: 202.169.129.40

Trying DNS
Name: bom3.vsnl.net.in
Address: 202.54.1.82

> set q=mx
> bom3.vsnl.net.in
Name Server: dns1.bplnet.com
Address: 202.169.129.40

Trying DNS
bom3.vsnl.net.in preference = 0, mail exchanger = mmb3.vsnl.net.in
vsnl.net.in nameserver = dns.vsnl.net.in
vsnl.net.in nameserver = md2.vsnl.net.in
vsnl.net.in nameserver = ss585.ncst.ernet.in
vsnl.net.in nameserver = naamak.ncst.ernet.in
vsnl.net.in nameserver = giasbm01.vsnl.net.in
mmb3.vsnl.net.in internet address = 202.54.1.85
dns.vsnl.net.in internet address = 202.54.1.30
md2.vsnl.net.in internet address = 202.54.6.20
ss585.ncst.ernet.in internet address = 202.141.150.18
naamak.ncst.ernet.in internet address = 202.41.110.66
giasbm01.vsnl.net.in internet address = 202.54.1.18

-----------------------------------------------

everything is similar like the above for all the domains whose
mails are in queue.


Can anyone help me to identify the cause for it.
whether it is mail server problem / our DNS server problem
or the destination domain's problem

Thanks in Advance

Regards,

Roobala

[Anu Mathew]

Hi Roobala,

Could this machine ever send a mail successfully out? If yes, I would suspect your DNS configuration.

Looks like the 1st DNS server, dns1.bplnet.com, is too busy at times to entertain a query from your mail server. What I would suggest is to route the DNS queries to the other name server of your DNS provider.

DNS queries are done in the order of nameserver entries in the /etc/resolv.conf . Upon receiving a time-out, the resolver's behaviour is very much based on your /etc/nsswitch.conf.

For example, if your /etc/resolv.conf has entries like:

nameserver dns1.bplnet.com
nameserver dns2.bplnet.com
namerserver dns3.some-isp.foo

To try a different Name server, say dns3.some-isp.foo, (since the dns1.bplnet.com appears to be busy) move that like to the top and down-grade the line with dns1.bplnet.com

ie,

namerserver dns3.some-isp.foo
nameserver dns2.bplnet.com
nameserver dns1.bplnet.com

Then, check up the nsswitch.conf. I would suggest an entry like

hosts: dns[NOTFOUND=return UNAVAIL=continue]

Then finally, I suggest running more queue-runners frequently with lesser time-out options defined.

(I assume that you've a link wide-enough for DNS queries to the name servers.)

Hope this helps.

Anu Mathew

[Uday_S_Ankolekar]

Hi,

What is your smarthost..?? I mean DS flag in sendmail.cf
Also check /etc/resolve.conf and DNS setup.

Good luck

-USA...

[Sridhar Bhaskarla]

Roobala,

Looks like your system is being nslook'able
on the other side. Is your domain properly deligated?.

Try like this.

telnet bom3.vsnl.net.in 25

(if the connection is successful )

helo bom3.vsnl.net.in
(....)
vrfy camentr

Or if you have a dedicated Smart relay host, try DS macro as suggested by Uday.

-Sri

[roobala]

Dear All,

Thanks for the suggestions,
I tested the server further , and got confirmed with the following.

1. With Sendmail 8.11.0 and HPUX 11.00 version to the said domains, mails are not going , it has been tested from more than 10 physical servers. (10 servers of same config, O/S, Same Sendmail versions),

Provided the DNS which has been used by this 10 servers are different, not the same.

2. from same our domain with Sendmail version 8.8.6 or 8.9.3 on HPUX 11.00 could send mails to those domains without any problem.
These mail servers also using same DNS Server, I mean dns1.bplnet.com.

This shows the problem is not with the DNS Server/Servers of our domain.

Only problem can be with Sendmail Files.

3. In sendmail.cf file there is no entry for DS macro as U asked. Similarly the other 8.9.3 server also has no entry.

resolv.conf, nsswitch.conf of all the servers, (8.11.0 , 8.8.6, 8.9.3 ) are same.

Now in sendmail what could be the problem? which will comeout with the error like this.

Thanks and regards,
Roobala

[Marco Paganini]

I've seen different versions of sendmail behaving differently when you don't have your DNS properly setup. I'd suggest a few steps:

- Check /etc/mail/nsswitch.conf (or the equivalent file, depending on how you configured sendmail) to make sure you have "DNS" enable for queries

- Check your /etc/resolv.conf file and leave only one DNS server there

- Save your original /etc/sendmail.cf file and copy over a file from a similar server that is working. You may have to "hammer" this file a little bit if versions are too far apart.

Hope it helps in any way.