Calling all networking gurus.

Discussion in 'Network questions and troubleshooting' started by Kaktus, Nov 23, 2011.

  1. Kaktus

    Kaktus Master Guru

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    Hi guys.

    I need help on something. Hopefully there is someone here who has studied networking or server related courses.

    I'm going to try and explain it the best i can so here goes.

    We have lets say a wisp business that has 100 clients.
    We have lets say 10 adsl lines.
    We have 3-4 different adsl ISPs.

    Now the problem is because we use different ISPs we have the problem of having to use different smtp email settings for our clients.

    1. Is there a way to set up an email server which can either reroute all emails to one dedicated adsl line dedicated for outgoing emails?

    2. Or to setup a smtp type server so that all the clients can use one smtp setting regardless on what "isp" they are.

    So to refresh we have many clients using different smtp settings but it becomes a HUGE pain in the butt when 1 adsl line goes dead and you need to route all of them to a different adsl line which results in their emails not sending either..... Which means we have to help all of them over the phone changing smtp settings or having to make callouts which n turn wastes valuable time... Only to change it again when the adsl line works again.

    Please feel free to ask any questions.

    Regards
    Hugo
     
  2. Black_ice_Spain

    Black_ice_Spain Ancient Guru

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    im not an expert, but cant you use "domain" which you control (aka virtual address), so they are called isp1,isp2,isp3,isp4, clients put that SMTP?, when one goes down, simply change the virtual address to aim other real SMTP.

    So instead of client changing their SMTP address, you simply change the real address associated with the virtual address they configured on their PC.

    Idk if its even possible but well, an idea...

    PD: With domain/virtual address i mean something like dyn-dns/no-ip services.
     
    Last edited: Nov 23, 2011
  3. att_user

    att_user Banned

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    The ultimate solution to this would be to set up an external mail server which can be accessed via the internet.

    Maybe one of your ISP in your region offers server or virtual server hosting. Here in germany you can get a virtual server for your homepage including a mail server with about a 100 to 200 email adresses included for about 10 € per month. For a business it would be recommendable to rent your own server machine which costs about 50 € or more depending on the provider.

    If you want to setup an inhouse mail server you can do that too. You just have to make sure that every client has access to that mail server. Setting up the SMTP on the client machines would not be too hard as long as you use a unique mail adress for the server. SMTP settings are independent of the ISP used.

    I just don´t get why you use 4 different ISP and 10 different ADSL lines. This makes only sense as long as the clients are in different locations/buildings. If your clients are all in the same building you will be better off building a LAN with a central router to which you can connect your ADSL gateway and your mailserver. If the lines are good enough you might even cut down costs and use only 1 ADSL line and 1 ISP for the future.
     
    Last edited: Nov 23, 2011
  4. Kaktus

    Kaktus Master Guru

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    Thanks for trying to help guys.

    @att_user

    Maybe i was not clear enough about the setup.
    Let me try again.

    We have the following scenario....

    We have over a 100 computers, each one of them with an email address on it. Whether that is a gmail, hotmail, yahoo or whatever you can think of it might have it on it.
    Each of these computers are at a different location or premises.
    The only way these are "connected" to each other is via a wireless network.
    The only thing this wireless network does is supply every one of these computers with an internet connection.
    So that means that each of these computers need smtp settings for their outlook etc...

    My problem is that whenever one of my ISPs have a downtime, a percentage of these computers experience an internet blackout. Which in turn means that if i "switch" the effected computers over to the other working ISP the smtp settings does not work anymore due to it being a different ISP.

    Now i understand that having all of the accounts at the same ISP might sound like the easiest solution. BUT that is not an option as i have different ISPs as a backup in case one of them are experiencing problems.
    Now that might sound like something thats not happening a lot, but we have learned our lesson the hard way in the past with only having one isp. The issue here is these computers can't be without internet for any given time... The same goes for the email.

    So my question is, if it is possible to somehow make a dedicated "smtp server".

    So that email can be send regardless of what ISP you switch your computers to.
    If that is indeed possible.
    How the hell do i do it... :nerd: :3eyes:
     

  5. att_user

    att_user Banned

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    This should not be the case. For example one of your client computers uses an Yahoo email address. Then you configure that account in your Outlook email account settings. The only thing bound to the email account in Outlook should be the port number of the mail server and the account login data. So it should be bound to the Yahoo email server where that account resides.

    How the connection is established to the email server is not included in SMTP.

    You might get a routing problem or a DNS problem but no SMTP problem.

    Maybe it will become clearer to you if you have a look at the OSI layer model here: http://en.wikipedia.org/wiki/OSI_model

    Nevertheless you can setup your own mailserver. Just install one of the major linux distributions on a computer. I would suggest Debian linux for that pupose as it is a free distribution. Then configure the sendmail demon and you are set. But if you do that you have to change all the external adresses to internal ones and communicate these changes to all your business contacts. That however gives you total control over all email parameters. You might want to include a spam control software and a firewall too.

    I found a link to a free mailserver linux distribution based on Debian linux here http://sourceforge.net/projects/deepofix/ and http://www.deeproot.in/. There you should be able to download it. It comes with pre configured packages and pre installed mail server environment, spam control soft, anti virus soft and a firewall. And it has a configuration program installed for configuring the mail server and mail relay.

    Another option would be to set it up as a mail relay server. In that case you have to configure all the different accounts on that relay server and set all your clients to communicate to the mail relay.
     
    Last edited: Nov 23, 2011
  6. Kaktus

    Kaktus Master Guru

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    Thanks man. I'll read into it.. Lots of info to keep me busy:)
     
  7. att_user

    att_user Banned

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    How do you switch over your disabled clients? Do they just change the WLAN network they are assigned to? Do you have a different gateway running for every ISP?
     
  8. Kaktus

    Kaktus Master Guru

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    Hi.
    No we use Mikrotik routerboards.
    So basically we just change the affected ip range to a different telephone number. The telephone number is representing the adsl/isp line here.

    It's difficult to describe if you do not now how mikrotik works but that's basically what happens.
     
    Last edited: Nov 24, 2011
  9. att_user

    att_user Banned

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    That is strange. In germany we have a lot of different ISP but if the lines are down you cannot get a connection no matter what your ISP is. If the ISP is down then you could switch to another ISP. But if you do that you only have to chang the ADSL login data in the dsl modem and you would be good to go.

    Maybe it is a DNS problem. Did you try to use a different DNS server in your router configuration, one that is not bound to your ISP? For example you could try the Google public DNS server 8.8.8.8 and 8.8.4.4. I use that DNS server too because it is much faster than my ISP DNS server.
     
    Last edited: Nov 24, 2011
  10. Kaktus

    Kaktus Master Guru

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    Hi bud.

    I'm afraid that is not possible.
    We are unable to change any settings on the routers. It's preconfigured business account routers, so our ISPs configure these routers before they send it of to us.
    If something goes wrong with the router they log in to the router from their side.

    Sorry about the confusion. I meant to say if and isp has a problem then we change over to another isp... But that means we use a different line as well since these adsl routers are locked on 1 specific telephone number.

    What i meant earlier about the mikrotik routers is, we use these routers as an internal router which routes and firewalls all the different adsl lines
    to our clients. Basically like a server would do.

    Here is a link to some of it so you can see what i meant, it's not the adsl routers.
    http://www.scoopdistribution.co.za/index.php?cPath=100
     

  11. att_user

    att_user Banned

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    Then try and set the DNS server static to 8.8.8.8 within windows ip settings.

    [​IMG][/url][/IMG]

    Does it happen often that you have to change the ISP?

    Another thing you could try is opening the windows command console after you reassigned a new ISP and type "ipconfig /release" and "ipconfig /renew" and then test if the email client is working.
     
    Last edited: Nov 24, 2011
  12. Kaktus

    Kaktus Master Guru

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    Hi.

    Yeh we use dns's 168.210.2.2 and 169.95.1.1.

    Will try that next time we are experiencing problems.
    Thanks.. :)
     
  13. att_user

    att_user Banned

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    Maybe you try this DNS Benchmark. It will show the fastest DNS servers for your connection.

    http://www.grc.com/dns/benchmark.htm

    I just ran that benchmark and it showed that 169.95.1.1 is not responding to DNS and 168.210.2.2 is a very slow server.
     
    Last edited: Nov 24, 2011
  14. grunger

    grunger Ancient Guru

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    One ISP's mail relay will not process mail from a client machine that is not on thier network for obvious reasons....

    So you could

    A. Use an auth'd SMTP server of for all the clients so ISP A's mailserver will send mail for ISP B's clients - but you will need a login to set this up - and will have to pay for this of course

    B. You could use someone like MessageLabs (Or Symantec Cloud as they are now) to send, but I think you have to pay for thier inbound filtering to get this

    C. Or you can setup a mail relay of your own, but if you do this make sure you get it right - SPF's etc otherwise you'll spend the next 6 months chasing mail bounces...

    D. Use a hosted Exchange solution, Exchange is 100 times better than any consumer grade email yahoo, gmail (and by that I also means the complete joke that is 'Gmail for Organisations') etc
     
    Last edited: Nov 27, 2011

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