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Firewall/Router issue last night, now exchange fails to send to some servers

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  • Firewall/Router issue last night, now exchange fails to send to some servers

    Hello all, i hope someone can help. I hope this is the right forum to post in.

    We had an issue with our router and connection to our hardware firewall last night, that was rectified with a new router and new broadband settings (And a new IP).we now have internet access and emails. But when we try to send to certain domains, we get a bounceback that it was rejected due to security policies.

    I'm adamant nothing was changed on the server due to this, but i'm a bit stumped as to why this would suddenly happen when it was all working fine 2 days ago.

    I have read that it could be to do with us now not being authenticated and the server we're sending to requires that. if that's the case, how to i rectify what happened yesterday?

    Any help would be greatly appreciated.

    Thanks.

  • #2
    Re: Firewall/Router issue last night, now exchange fails to send to some servers

    Have you made sure that your domain name (the sending SMTP domain which your mail server announces itself as) is properly associated with the new IP? Make sure the @ records are correct.

    Also, some DNS servers may not update their cache with the new domain = IP for some time which may cause issues.

    I would also check spam black-lists to make sure your IP is not appearing on them. Sometimes, just being within an IP range is enough to get you blacklisted (when it's AOL).

    Check the NDR notification very carefully and follow any links - the answer may be there.
    A recent poll suggests that 6 out of 7 dwarfs are not happy

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    • #3
      Re: Firewall/Router issue last night, now exchange fails to send to some servers

      Hi there. Cheers for the reply.

      Maybe I should have mentioned that we use messagelabs for antispam, so our MX records go through their servers, IE cluster8.eu.messagelabs.com.

      I have logged into our antispam and updated the inbound routes which allowed email traffic to start flowing. We can send messages to about 95% of domains.

      I was thinking that perhaps the DNS records hadn't fully propagated yet, as i know it can take over 24 hours, but i was a bit confused as to why the majority of the email was working pretty much instantly.

      I've just done a blacklist check on mxtoolbox and get a timeout on CHOON but the rest are ok.

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      • #4
        Re: Firewall/Router issue last night, now exchange fails to send to some servers

        Just to add, I checked over the bounceback in a bit more detail and found this:

        [email protected]
        atl4mhib23.myregisteredsite.com #554 5.7.1 The message from (<[email protected]>) with the subject of (RE: No Subject) matches a profile the Internet community may consider spam. Please revise your message before resending. ##

        I tried resending the email above with a subject and a body of text but it still bounced with the same error...

        Also, when running another blacklist scan on whatsmyip, we're apparently blacklisted on http://www.apews.org/ which, according to whatsmyip they say "Whatismyipaddress.com does not recommend the usage of this blacklist. It has the potential to block large segments of IP addresses. If you are listed with them it is generally not a problem."
        Last edited by hitchin669; 20th February 2014, 18:14. Reason: More info

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        • #5
          Re: Firewall/Router issue last night, now exchange fails to send to some servers

          Ah, yes - I think that is the same blacklist that an organisation I provide support for ended up on. They were having issues sending to AOL addresses. AOL have a dumb security system which tends towards knee jerk responses and had blocked emails from this IP simply because it appeared in a 'bad' IP range. They had absolutely no evidence that any mail from the IP in question had been classified as spam.

          We also used Message Labs several years ago. I recall their tech support was excellent. Assuming they still use the same people after the take-over by Symantec, you will probably have more luck discussing your issue with them. They have all the tools immediately to hand and can probably offer you some very sound advice.
          A recent poll suggests that 6 out of 7 dwarfs are not happy

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          • #6
            Re: Firewall/Router issue last night, now exchange fails to send to some servers

            That's interesting. We've had issues sending to AOL that date back years, before i started with the company and no one knew how to fix it?!

            I had a potential brainwave..We only used MessageLabs for inbound routes, so surely using Outbound too would mask our IP and potentially sort the issue out?

            I've spoken to them, you're correct, fantastic customer support, and set up everything i need and hopefully fingers crossed this sorts the issue out...!

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            • #7
              Re: Firewall/Router issue last night, now exchange fails to send to some servers

              Excellent! I hope it is soon resolved.
              A recent poll suggests that 6 out of 7 dwarfs are not happy

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              • #8
                Re: Firewall/Router issue last night, now exchange fails to send to some servers

                I've emailed a colleague who had a bounceback issue, and so far they've had nothing back and it's been 15 minutes! So looking good. I had no idea you could set up Messagelabs to be outgoing...I'll know for next time!

                Thanks for your help and steering me in the right direction! I'll report back tomorrow when the hopefully happy customer has emailed us back!

                Thanks.

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                • #9
                  Re: Firewall/Router issue last night, now exchange fails to send to some servers

                  Hi Blood.

                  Just to let you know, all is working fine now! No bouncebacks at all today!

                  Thanks once again for your help!

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                  • #10
                    Re: Firewall/Router issue last night, now exchange fails to send to some servers

                    You're welcome

                    Thanks for posting back
                    A recent poll suggests that 6 out of 7 dwarfs are not happy

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