Sendmail/qmail nameserver problem

Hi,

my RedHat 7.3 system which has been working fine for a long time got
an odd problem when I upgraded to broadband. I've tried to ask about
this in comp.mail.sendmail but have received no useful replies so far.

My sendmail is RPM version sendmail-8.11.6-27.73. I'm connecting with
a SpeedTouch 510 ADSL modem/router.

The problem is that when I try to send an email, I get error messages
like the following:

Dec 5 23:57:57 widmann sendmail[4347]: hB5KbP101657: to=(E-Mail Removed), ctladdr=twid (500/500), delay=03:20:32, xdelay=00:00:00, mailer=esmtp, pri=1740028, relay=mdi92.dk., dsn=4.0.0, stat=Deferred: Name server: mdi92.dk.: host name lookup failure

However, mdi92.dk seems to be absolutely fine:

~> ping mdi92.dk
PING mdi92.dk (212.242.222.121) from 10.0.0.1 : 56(84) bytes of data.
64 bytes from port56.ds1-arno.adsl.cybercity.dk (212.242.222.121): icmp_seq=1 ttl=48 time=82.7 ms

I've also tried to add a smart host but it didn't help. I get entries
like the following in the log:

Dec 7 00:46:49 widmann sendmail[8120]: hB5Kcsx01665: to=(E-Mail Removed), ctladdr=twid (500/500), delay=1+04:07:55, xdelay=00:00:00, mailer=smtp, pri=3270028, relay=smtp-1.mail.ptstream.co.uk, dsn=4.0.0, stat=Deferred: Name server: smtp-1.mail.ptstream.co.uk: host name lookup failure

Replacing the name with its IP address didn't help:

Dec 7 00:31:35 widmann sendmail[7826]: hB5KbP101657: to=(E-Mail Removed), ctladdr=twid (500/500), delay=1+03:54:10, xdelay=00:00:00, mailer=smtp, pri=2820028, relay=217.79.112.6, dsn=4.0.0, stat=Deferred: Name server: 217.79.112.6: host name lookup failure

It has nothing to do with that server, since I am able to telnet to it
on port 25 and send emails succesfully.

I'm starting to think it is not a problem with sendmail, since I tried
to install qmail instead but still got equivalent errors, e.g.:

Dec 7 00:04:23 widmann qmail: 1070755463.079608 delivery 18: deferral: Sorry,_I_couldn't_find_any_host_by_that_name._(#4. 1.2)/

All other applications seem to have no problems (for instance, I'm
able to post this).

I'm using the following m4 file:

divert(0)dnl
VERSIONID(`twid on 05/12/03')
OSTYPE(linux)dnl
FEATURE(`accept_unresolvable_domains')dnl
FEATURE(`accept_unqualified_senders')dnl
DOMAIN(generic)dnl
MAILER(local)dnl
MAILER(smtp)dnl

(The two feature lines were necessary in order to receive email from
my work address, but that's not the main issue here.)

For the smart host example, I added
define(SMART_HOST, smtp:smtp-1.mail.ptstream.co.uk)

Any ideas what's wrong?

/Thomas
--
Thomas Widmann (E-Mail Removed) http://www.twid.bibulus.org
Flat 3/2, 54 Mavisbank Gardens, Glasgow G51 1HL, Scotland, EU
*** Ny gruppe om nordiske sprog: europa.linguas.germanic.nord ***

Thomas Widmann <(E-Mail Removed)> writes:

>my RedHat 7.3 system which has been working fine for a long time got
>an odd problem when I upgraded to broadband. I've tried to ask about
>this in comp.mail.sendmail but have received no useful replies so far.

>My sendmail is RPM version sendmail-8.11.6-27.73. I'm connecting with
>a SpeedTouch 510 ADSL modem/router.

>The problem is that when I try to send an email, I get error messages
>like the following:

>Dec 5 23:57:57 widmann sendmail[4347]: hB5KbP101657: to=(E-Mail Removed), ctladdr=twid (500/500), delay=03:20:32, xdelay=00:00:00, mailer=esmtp, pri=1740028, relay=mdi92.dk., dsn=4.0.0, stat=Deferred: Name server: mdi92.dk.: host name lookup failure

>However, mdi92.dk seems to be absolutely fine:

>~> ping mdi92.dk
>PING mdi92.dk (212.242.222.121) from 10.0.0.1 : 56(84) bytes of data.
>64 bytes from port56.ds1-arno.adsl.cybercity.dk (212.242.222.121): icmp_seq=1 ttl=48 time=82.7 ms

Have you tried an MX record lookup?

Typically these router boxes set themselves as a DNS proxy. But some
of them give incomplete DNS support.

You can either list your ISP nameservers in "/etc/resolv.conf",
or you can try running your own DNS server.

>I've also tried to add a smart host but it didn't help. I get entries
>like the following in the log:

>Replacing the name with its IP address didn't help:

>Dec 7 00:31:35 widmann sendmail[7826]: hB5KbP101657: to=(E-Mail Removed), ctladdr=twid (500/500), delay=1+03:54:10, xdelay=00:00:00, mailer=smtp, pri=2820028, relay=217.79.112.6, dsn=4.0.0, stat=Deferred: Name server: 217.79.112.6: host name lookup failure

You have to put an IP address in brackets -- as in [217.79.112.6] .

>It has nothing to do with that server, since I am able to telnet to it
>on port 25 and send emails succesfully.

Maybe your router is resolving A records, but not MX records.

Neil W Rickert <rickert+(E-Mail Removed)> writes:

> Thomas Widmann <(E-Mail Removed)> writes:
>
> >The problem is that when I try to send an email, I get error messages
> >like the following:
>
> >Dec 5 23:57:57 widmann sendmail[4347]: hB5KbP101657: to=(E-Mail Removed), ctladdr=twid (500/500), delay=03:20:32, xdelay=00:00:00, mailer=esmtp, pri=1740028, relay=mdi92.dk., dsn=4.0.0, stat=Deferred: Name server: mdi92.dk.: host name lookup failure
>
> >However, mdi92.dk seems to be absolutely fine:
>
> >~> ping mdi92.dk
> >PING mdi92.dk (212.242.222.121) from 10.0.0.1 : 56(84) bytes of data.
> >64 bytes from port56.ds1-arno.adsl.cybercity.dk (212.242.222.121): icmp_seq=1 ttl=48 time=82.7 ms
>
> Have you tried an MX record lookup?

Not until now, and it failed... So that's the problem!

> Typically these router boxes set themselves as a DNS proxy. But some
> of them give incomplete DNS support.

Hmmmm, I wonder how to fix that.

> You can either list your ISP nameservers in "/etc/resolv.conf",

I believe /etc/resolv.conf is overwritten at boot time since I'm using
DHCP.

> or you can try running your own DNS server.

If I could avoid that, it's be nice.

> >I've also tried to add a smart host but it didn't help. I get entries
> >like the following in the log:
>
> >Replacing the name with its IP address didn't help:
>
> >Dec 7 00:31:35 widmann sendmail[7826]: hB5KbP101657: to=(E-Mail Removed), ctladdr=twid (500/500), delay=1+03:54:10, xdelay=00:00:00, mailer=smtp, pri=2820028, relay=217.79.112.6, dsn=4.0.0, stat=Deferred: Name server: 217.79.112.6: host name lookup failure
>
> You have to put an IP address in brackets -- as in [217.79.112.6] .

Yes, that works! Thanks a lot!

> >It has nothing to do with that server, since I am able to telnet to it
> >on port 25 and send emails succesfully.
>
> Maybe your router is resolving A records, but not MX records.

Yes, that seems to be the case. :-(

/Thomas
--
Thomas Widmann (E-Mail Removed) http://www.twid.bibulus.org
Flat 3/2, 54 Mavisbank Gardens, Glasgow G51 1HL, Scotland, EU
*** Ny gruppe om nordiske sprog: europa.linguas.germanic.nord ***

Thomas Widmann wrote:
>Neil W Rickert <rickert+(E-Mail Removed)> writes:
>> Typically these router boxes set themselves as a DNS proxy. But some
>> of them give incomplete DNS support.
>
>Hmmmm, I wonder how to fix that.

You can put the IP numbers of the nameservers of your ISP in
/etc/resolv.conf and tell your dhcp client not to overwrite it.
The man-page should tell you which option to use, look for something
like:
-R Prevents dhcpcd from replacing existing
/etc/resolv.conf file.

--
Maurice mauricej (at) xs4all (dot) nl