Marco van Beek via GLLUG wrote:
On 10/10/2022 22:54, Ken Smith via GLLUG wrote:
I'm trying to sort out a Rocky 8.5 server that has sendmail
installed. (Please don't go on a diversion about how I should tell
the owner to dump sendmail and switch to exim or postfix - save that
for another thread please. )
I'm pretty good with sendmail but this problem has me a bit foxed.
I'd value some suggestions of where to look as I think I'm not seeing
the wood for the trees.
It will send from addresses in the local network, without auth,
because I have "connect:192.168.123 relay" in the access file -
that being the local LAN.
I've tested sasl auth and that is authenticating.
Using telnet from an IP off their LAN (over a VPN) I can connect
using TLS (openssl s_client etc etc) and authenticate (perl
-MMIME::Base64 etc etc) it accepts my credentials and then if I try
to send a message I get "Relaying denied. IP name lookup failed [my
local ip]" The same happens with a test using Thunderbird.
If I do the same test from the host that sendmail is on, it works fine.
Also if I do the same test from another host on the same LAN it works
fine.
Somehow its complaining about the source IP in authenticated sessions
outside the LAN range.
In the test from my local LAN (172.16.0.x), over a VPN, the remote
dns can't resolve the reverse dns of my LAN. I've done a similar test
with another sendmail site and remote auth is working fine.
Maybe sendmail is doing reverse DNS when it shouldn't be.
Suggestions most welcome....
Thanks
Ken
Hi,
It might be the difference between a missing entry in a zone file, and
a missing zone file. Maybe it is the lookup mechanism that fails,
rather than it checking the IP address itself. It might be another
rule set that is trying to do a reverse lookup (eg hostname), and it
barfs out at that point.
Maybe increase the logging verbosity and check the logs again?
Cheers,
Marco
Thank you - Not sure where my error was but, probably a typo on my
part. I reconfigured it from the ground up using the template config
files I've kept from other setups and its working fine now. Didn't touch
any thing to do with DNS or /etc/hosts.
All fixed. Yay :-) Ken
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