slow email delivery... (bulk mail)

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oROEchimaru

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I am an IT specialist for a publishing company and am running out of ideas. The software we use is called imail, and I am working with their tech support. We send out about 300k messages a day, but usually at 50k/hour bursts... this worked fine for over a year until december.

1. we have raid 5 scsi, 2x2dual core xeons, 6gb ram, win2k3
2. we have 10mbs up/down constant connection

For some reason our email lately is leaving port 25 very very slowly. We send email to the mail server at about 30 messages a second... the mail server is only kicking out emails at about 3-10 messages a second... after about an hour our "queue" builds up and we have 50k messages waiting to be delivered. Then... if we need to send new emails or test what we plan on sending out... we have to wait 1-2 hours to receive our tests.

Do you guys have any ideas or tweaks for a win2k3 server? We are behind a cisco firewall and have a fast server. We are pulling hairs over what to do next. I reset the tcp settings, updated drivers, updated imail's software etc... slow. Any ideas?
 
imail and campaign enterprise (ipswitch imail)...

we are thinking dns too...

i am going to see if they time out today... hopefully not. the thing was is we were using time warner's dns... i wonder if that was timing us out.
 
We publish print magazines for the railroad, cleaning and building/facility management industries. Our mail database members are from people that signed up, went to our trade shows or are subscribers to our magazines... with signoff lists (follow legal requirements of bulk mail)..

It amazes me how active the rail road industry is in the online world.
 
jroe52 said:
imail and campaign enterprise (ipswitch imail)...

we are thinking dns too...

i am going to see if they time out today... hopefully not. the thing was is we were using time warner's dns... i wonder if that was timing us out.
Click to expand...

Time Warner's DNS servers are crap. I would suggest setting up an internal cache at the minimum.
 
do you have any info on that? i read something about having a dns program... that might speed things up... we need

1. we need valid reverse dns records
2. valid zone transfers

this way our mail is not blocked by spam. we were getting 1/4 ping attempts through! what crap from tw. 3/4 pings would fail to their server! so we are trying a tsr dns as a temporary solution but it will not match our reverse dns/zone transfer records.

ns1.milw.twtelecom.net 216.136.95.2 216.136.80.0/20
 
You have two thing you need to look at for DNS:

First is hosting of your forward lookup zone for your company. You can use the services from your registrar for this, or there are plenty of third party companies that will host it. I would set your TTL values anywhere from 6 to 24 hours. This will help reduce the number of queries that need to be performed by recipient mail servers by allowing them to cache the result longer. You need to give TW a call for the reverse lookup record for your mail server. They control that zone, so any changes have to go through them. They usually do this for business class customers.

The bigger problem with TW's servers are the forward lookups. Your mail servers are generating a ton of lookups for out bound mail. Installing a local cache would greatly help reduce that load. I have had a ton of problem with TW's forward lookup servers. If you set up a local cache server, you could configure it to forward to a more reliable server. I personally use OpenDNS for all of my clients to forward to.
 
thanks for the reply. are there any other win2k3 settings maybe that were modified by mistake that anyone can think of?

I talked to my supervisor, he has the server setup correctly as mentioned in your post. This is what I posted on imai'ls forums...



***
1. bad dns server (Switched) (we tried two good ones)
2. invalid dns blacklists , to many black lists (we have 2 good ones)
3. slow server (we have 6gb ddr2, raid 5 scsi, 2xdualcore xeons)... not slow
4. a slow connection (we have 10mbs up/down )
5. a port 25 blocked by the firewall (ours is not blocked... ours is good)
6. to many rules (we have 1-2 that delete email to -bounce accounts)
7. bad drivers... (we updated drivers... no difference)

any other ideas? we have this issue with 9.2, 9.21, 9.23 and 9.23beta

we have tried 1000 threads, 800, threads 100, 80, 60 etc... all equally slow.

our problem:
for 2 years we sent 50k emails an hour or more through imail with no problems. at the end of that hour you could send an email and get it instantly, you could even send another 50k. the queue would be between 5000-20000. For the last month at the end of the hour, the queue is still at 50k or more... if you try sending email to yourself you will not get it for one hour! (instead of 1 minute or less).
 
Is there any thing in your logs about recipients rate limiting you or not accepting connections?
 
timeout means the connection was dropped or lost. Sure you don't mean time_wait?
time wait is the state after the connection has been finished, but it sticks around to handle any extraneous packets so they don't case problems.
 
ok shew... time_wait was it... thanks for the explanation!

we still are having slow email delivery rates. we got the services to stop crashing but we are sending out 25k an hour when we need to do 75k an hour. we have tried several different dns servers...

we do get a lot of bounce back messages that could be hurting the queue's performance... we have most setup to be deleted however.
 
tw telecom.. our isp if we use their dns it crashes the server for email delivery

anyone know of fast, reliable dns servers that allow thousands of connections each day? i am worried some public servers would throttle us. any ideas?
 
jroe52 said:
tw telecom.. our isp if we use their dns it crashes the server for email delivery

anyone know of fast, reliable dns servers that allow thousands of connections each day? i am worried some public servers would throttle us. any ideas?
Click to expand...

Run your own, setting up caching DNS servers isn't all that difficult.
 
any direction you could send me too with examples?

we currently have a dns server with our mail records (mx/a/names/ptrs) etc... is this what you are referring to?

if not... i think you might be talking about programs like treewalk... how are these in handling dns queries?

incase it is not a dns issue... any ideas on tweaking tcp in win2k3?
 
No, a caching DNS server is bit of a different concept, but you can run them both on the same machine. How ever in your case I would not suggest it due to the load your mail server is creating. What OS did you want to run this on, Windows or some *nix variant. I have more experience with bind which runs on both but if you are using Windows I would just suggest the Microsoft DNS service. With the kind of load you are generating with all of the queries I would suggest getting a dedicated box to handle this, you won't need much in hard disk space and queries aren't too CPU intensive but when you start doing a lot they build up quick, and if you can get 2 little machines to spread the load out and have some redundancy that would be even better.
 
we are using win2k3 for the mail server. we could use a nother win2k3 if it had to be a dns cache.

how do you use the windows dns service as your dns cache, rather than an ip address.... so we can call this by ip address for our email delivery?
 
jroe52 said:
we are using win2k3 for the mail server. we could use a nother win2k3 if it had to be a dns cache.

how do you use the windows dns service as your dns cache, rather than an ip address.... so we can call this by ip address for our email delivery?
Click to expand...

Well if you installed the DNS service (add remove programs -> windows components) and configure that service to do recursive DNS, then configure your mail server to use it for DNS resolution (configure the network interface, and you can set it there in the TCP/IP properties). I do not know the specifics on how to configure Microsoft DNS service do do recursive DNS though so you might need to check out technet for more on that.
 
but our mx and ptr records are stored on a different server... that has dns...

should i make the change there?
 
jroe52 said:
but our mx and ptr records are stored on a different server... that has dns...

should i make the change there?
Click to expand...

As I mentioned before, there is a difference between your public domain name (mydomain.com) and an internal cache server that doesn't host a zone at all. I would suggest that you read up on DNS because it sounds like you are a little confused.

You shouldn't need to touch your public records or server. Just install the DNS service on a internal server (even the same server), then point the email server to use the internal server for its DNS settings. If you don't do any configuration of the DNS service, it will act as a cache only.
 
I did that last night we are testing it today. I was a little confused on how the email server communicates with our dns server.

At the DNS server's nic level... is it ok to point to itself as well at the internal address, or must it have an external DNS?
 
jroe52 said:
I did that last night we are testing it today. I was a little confused on how the email server communicates with our dns server.

At the DNS server's nic level... is it ok to point to itself as well at the internal address, or must it have an external DNS?
Click to expand...
If setup correctly it should be able to handle all of the DNS resolution itself with out reliance on outside systems. The one thing necessary for that to work optimally is an up to date root.hints file. This is the file that tells your DNS server the name and IP addresses for the DNS servers that handle the . (root) DNS zone. That doesn't mean you can't use your ISPs DNS servers on that machine and it doesn't have to use itself for DNS resolution at all, the idea is simply to use it to reduce the load on your ISPs DNS servers and hopefully have something more reliable for your mail servers.
 
we switched our smtp (in imail) and nic to now point to our internal dns server. this has reduced our email delay from 2 hours to 30 minutes, which is a good improvement but not perfect.

on the dns server itself... at the nic level... should it be pointing to itself as the dns (192.xxx) or an external site (time warner, TSR, ATT, open dns etc)... or both? if both... which should come first?

this dns server hosts our websites and dns information.
 
jroe52 said:
we switched our smtp (in imail) and nic to now point to our internal dns server. this has reduced our email delay from 2 hours to 30 minutes, which is a good improvement but not perfect.

on the dns server itself... at the nic level... should it be pointing to itself as the dns (192.xxx) or an external site (time warner, TSR, ATT, open dns etc)... or both? if both... which should come first?

this dns server hosts our websites and dns information.
Click to expand...

DNS in the TCP/IP properties should be pointed to its self only. If it's on the same server as your imail server, then imail should be pointed to its self as well.
 
MorfiusX said:
Time Warner's DNS servers are crap. I would suggest setting up an internal cache at the minimum.
Click to expand...

seconded... mine go down all the time... roadrunner business class DNS' are trash
i have opendns addresses as backup... for testing purposes i'd just shove that in there and see if it goes any faster...

opendns.com said:
Our nameservers are 208.67.222.222 and 208.67.220.220.
Click to expand...
 
if we have our own dns server (internal) do we need to still use an outside one? please read the last few posts...
 
You don't have to, but I would suggest continuing to use them for your other machines and leave your internal caching DNS server for the mail server to minimize the load. The idea is to allow your mail server to get the necessary DNS queries done as fast as possible and having more hosts query that server is just going to introduce additional load and likely slow things down.
 
still having slow email deliveries. imail is driving me crazy.

any other ideas? this is on win2k3...
 
I noticed while sending one campaign (about 22k emails in an hour period)... i have no problems, it runs at 100% speed. If I run 2 campaigns from two different databases using the same domain and email addresses... then the issues escalate and we have slow email delivery...


this is what i posted on their support forums:
We never had this issue until about a month ago.


If I send one email from one database.. at a rate of 22k an hour... (the database is the same size)... my objects never fill up in the queue.

If I send two emails, from two different databases from the same email addresses and domains.... then the queue fills up at a 1:1 ratio.. so if we send out 30k emails we'll have 30k emails waiting to be delivered or about 60k objects!!!

this never happened before January 15th... anyone have ideas?
 
I'm not familiar with iMail, but one common link you have mentioned are the databases. I would start looking at those to make sure they aren't the cause of the problem.
 
will do. i believe they are rather similiar... so if you run one at a time... its fine but if you run two (two different dbs) things get crazy. i'll look once the access dbs are unlocked and done being used.
 
its definently not the databases...

once the db is done being used... it is stored in imail's queue manager were it is then up to imail to make the deliveries or not. it is going at about 250 emails a minute... when it should be going at 700-1000 emails a minute.

i have never been this stressed out in my life it is taking its toll on me.
 
we are still having very slow email delivery. we resolved all our dns issues and now point to a working internal dns cache...

when we run 1 campaign... from one unique database/email account... and domain... it flies at 100% speed..

when we run a 2nd campaign... from its own unique stuff... it drops to less than 25% speed.... so after sending out 40k emails... 30-40k are still being wait to be sent an hour later!

if you run a 3rd campaign... its even worse. (queue objects 2x the size of record in database)... so if you sent 60k emails about 120k objects will be in the queue.

we have checked almost everything with imail.. any other ideas?
 
Contact your provider of the application, sounds like you need support from them at this point.
 
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