I originally posted this in the "Web Programming" forum and in discussions over there it seems that the issue I may be having is related specifically to the Exchange server I'm trying to use. I'm going to re-post my messages over here in the hopes that someone will be able to tell me why I can't do what I'm trying and why there seems to be inconsistencies in the data that I've been finding. Sorry for the long post, but I'm just trying to post everything I already asked in the other forum and the only thing anyone was able to suggest what that it was some sort of network security issue and that I needed to ask someone who knows Exchange very well. Thanks in advanced for any help/suggestions/solutions that you can provide. This is something very important to an application I'm developing and without it I lose a major function.
Below is a combination of post I had written over a 2 day period based on additional information users were asking for. I cut it back some, but I just want to make sure I provide everything I can:
I'm a VB.NET developer and I like to expand by knowledge by trying to program things from scratch that are already implemented in the the.NET framework. My current project is programming a SMTP server using just sockets. I've already read the RFC on SMTP and my company has an Exchange Server (2007) that I was going to use for testing.
The web address of the server is exchange.mycompany.com and I used reverse DNS to get the IP adress. The domain name does have a MX record a well. From the command prompt on my computer (which is running Win7 Professional) I tried using telnet to connect on port 25. I tried using the domain name as well as the IP address, but both times it said it couldn't connect to the server on port 25.
I checked the settings in Outlook and the port is correct. I then tried connecting on port 110, and some other ones that are sometimes used, and it gave the same error message.
Next I connected to the Exchange server through VPN and tried telnet again on port 25 and this time it worked. However in the SMTP banner it said remote.mycompany.com instead of exchange.mycompany.com. So I disconnected from the VPN and tried the telnet again on all the ports I initially tried but used remote.mycompany.com but again got the same error message. I did an IP address lookup and remote.mycompany.com and exchange.mycompany.com point to the same IP address.
I then used mxtools.com and dnsstuff.com (I think that was the adress) and used their SMTP tools to see of they could connect. I entered mycompany.com as the domain name and they looked up the MX record, which returns exchange.mycompany.com as the SMTP server, and both tools were able to connect with no issues identified.
So my questions: 1) If the MX record list exchange.mycompany.com as the SMTP sever, why does the banner return remote.mycompany.com? 2) Why can't I connect the SMTP server through telnet unless I'm connected through VPN, but the two websites I used to test it the connection worked?
Obviously the server works because because the two websites can connect to it, I can when I'm in VPN, and other servers can because I receive email on my corporate account. What could prevent my computer from connecting to the SMTP server through telnet when I'm not on VPN. I should also mention that I even tried turning off all my anti-virus software to make sure that it wasn't blocking it.
I was thinking maybe because I don't have a domain name so if the Exchange server tries to lookup the IP address of my computer there is no MX or PTR record. Is this something SMTP servers look for?
Just today I also found something that I don't know how to explain or how it may affect this. The MX record for the server list exchange.mycompany.com. However, even when I'm on VPN, I can't connect to the SMTP server using that address in telnet or the IP address it points to. I have to use remote.mycompany.com, which is shown in the SMTP banner and points to the SAME IP ADDRESS. Is there a setting in Exchange that makes it script only request coming from this address? If so, how do the online SMTP tools discover this subdomain when I only gave the tools the domain name (mycompany.com) and the MX record only shows exchange.mycompany.com? The address remote.mycomany.com is not located anywhere in the zone file.
What I'm trying to do (at least for now) is figure out how to deliver mail to the Exchange server from my software. For example, if I build an SMTP server and a client which connects to my that SMTP server and I want to send an email to firstname.lastname@example.org (where the SMTP server for mycompany.com is hosted on the Exchange server), how would the SMTP server I created connect to the Exchange server in order to deliver the email? Doesn't the Exchange server have to allow some sort of connection from outside the intranet in order to receive emails from other domains (gmail, yahoo, etc.)?
I have a problem with the installation of xamp on ubuntu 11.04.
I succesded to install it but when i click on phpmyadmin it outputs a message saying something like this "all files are not suppose to be made world writable". Plz who can help me solve this problem.
There are many managed solutions available. E.g.:
1. Sophos End point security and control
2. TrendMicro OfficeScan
3. McAfee VirusScan Enterprise
However, the best solution depends on your needs!
Some variables could be:
1. Support/ SLA
3. Configuration/Management options
4. Integration with existing infrastructure
5. Confidentiality requirements (e.g. connecting to Vendor's servers is not acceptable)
See the following web-sites to get a feel of performance of various AV products.
Depends which versions of Windows Servers you're running?
Forefront endpoint protection and System Center Endpoint Protection come with most licensing agreements with current Windows products.
As was pointed out:
TrendMicro is fairly good, which even MalwareBytes has a Enterprise version of their quality AV.
Manageability is a huge factor though, which cost is not far behind. A lot depends on existing Infrastructure like if you have a Firewall, IDS/IPS systems like Dell Secureworks, or other security blocks in place.
Hi coded people, I consider my self privileged to be in your mist today. Please I need a sound and good programmer to make me an SMS platform(gateway?) that will not charge me a dime to send unlimited SMS each time I use it, but a one-off payment or annual or monthly moderate billing will be okay. This platform will have to be something like textmark.com, but much smaller with a maximum of 8 users. Please anyone with recommendations, suggestion, or interest should reach me here or email:email@example.com or firstname.lastname@example.org or phone +2348188404908
Please note that i have no knowledge of programming whatsoever
I have a Linux box I use for a firewall with iptables, and I need to put my mail server on the right ip address for proper reverse DNS Lookup.
So I can take inbound packets and NAT them to the mail server, but I need to take outbound packets from the mail server, and send them on a different IP address. The IPTables sends everything out on the same IP, which is 1, but I need 5.
I thinking maybe I could add another gateway, using route, below is my main route, I'd like to add 192.168.3.5 to use a gateway of 126.96.36.199,
Am I on the right track here?, I could use some help on this
/sbin/route add default gw 188.8.131.52 dev eth0
/sbin/route add -net 192.168.3.0 netmask 255.255.255.0 gw 192.168.3.1 dev eth1
I had 2 addresses bound to the mail server adapter, and was only SNAT 1 of them, so I added a SNAT to the other address, and now the mail server responds on the correct ip address for reverse dns and resolves correctly.
So I didn't need a 2nd gateway address, or need to add any additional routing, turned out to be pretty easy. Only took me years to figure out.
I want to take all new smtp packets generated inside the network, and send them out on a different ip address, and not the gateway address, so the ipaddress reverses back to the correct ptr record, indicating it's a mail a server that belongs to my domain.
Right now, the packets go out on the gateway, with a different reverse ptr record.
I am facing a strange issue in a website, where the website goes down every day and when i recycle the website it comes back working and goes down the next day.
the website says connecting to the page and never connects when its down.
i have tried creating a separate Application pool and tried as well bit nothing seems to be working.
Its hosted in a NLBS mode where the a memory threshold algorithm used.
I have tried all the steps possible but nothings working,please help.
I am running Nginx with MySQL. The php5-fpm log reports the error fork() failed, how can I fix this?
If some one can help in understanding the configuration directives of Nginx, php5-fpm and MySQL, it would be great?
Hi I have a problem in subnetting, if anyone has an idea could help, the problem is: If I have 6 hosts and in a class A address, how do I get the number of subnets and the custom subnet mask if an given a network number 184.108.40.206, thank you.
I used the Microsoft Web Platform Installer to install mojoPortal into a website I created in IIS8 on Windows Server 2012, and whenever I try to go to one of the pages in the site, I get a 404 Not Found error. IIS has done this for several testing sites I have created, and it is getting annoying. Any suggestions on what could be going awry?
EDIT: I was able to get an error stating something about wildcard script maps. I will use that to look into other possibilities.
EDIT2: IIS seems to think that the .aspx file extension has no associated handler, but a handler for it exists in the list. I will look into this further. It might be a missing role/feature.
EDIT3: It turns out IIS wasn't redirecting correctly. I still need to figure out what went wrong there.
I think computer viruses should count as life. I think it says something about human nature that the only form of life we have created so far is purely destructive. We've created life in our own image.
modified 25-Sep-12 13:00pm.
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