Results 1 to 9 of 9
  1. #1
    Untangler
    Join Date
    Nov 2016
    Location
    Grafton, Australia
    Posts
    39

    Default emails stopped working after modem change

    Hi, I support a school with 200 students, running UT (Software) in ROUTER mode on a well spec'd HP server - a very simple topology, i.e. no DMZ's, no multiple subnets, all very simple. It has been running for several years (but I'm only recent on the scene) and have limited network knowledge.

    Untangle_Setup.jpg

    Everything has been working OK, but today we swapped over the ADSL modem due to minor intermittent comms issues (same ISP & account). I didn't want to change UT, so I ensured that the new modem had the same private IP as the old one. When installed, external web sites displayed OK, but emails stopped working. Remote Access from outside and internal web sites stopped working too.

    Any ideas about where I should start looking ?

    Thx, Wayne
    Last edited by Pilotpak; 08-10-2017 at 06:06 AM.

  2. #2
    Untangler
    Join Date
    Mar 2016
    Posts
    31

    Default

    Quote Originally Posted by Pilotpak View Post
    Hi, I support a school with 200 students, running UT (Software) in ROUTER mode on a well spec'd HP server - a very simple topology, i.e. no DMZ's, no multiple subnets, all very simple. It has been running for several years (but I'm only recent on the scene) and have limited network knowledge.

    Untangle_Setup.jpg

    Everything has been working OK, but today we swapped over the ADSL modem due to minor intermittent comms issues (same ISP & account). I didn't want to change UT, so I ensured that the new modem had the same private IP as the old one. When installed, external web sites displayed OK, but emails stopped working. Remote Access from outside and internal web sites stopped working too.

    Any ideas about where I should start looking ?

    Thx, Wayne
    Maybe the new modem in in "router" mode (instead of bridged / passthrough) as well, or has a firewall enabled, if so then the inbound traffic will probably not be passing through it.

  3. #3
    Untangle Junkie dmorris's Avatar
    Join Date
    Nov 2006
    Location
    San Carlos, CA
    Posts
    17,747

    Default

    Yes, according to your diagram your modem is doing NAT. You need to configure port forwards on your modem.
    Attention: Support and help on the Untangle Forums is provided by volunteers and community members like yourself.
    If you need Untangle support please call or email support@untangle.com

  4. #4
    Master Untangler TirsoJRP's Avatar
    Join Date
    Oct 2010
    Posts
    468

    Default

    Check your modem options and make sure the needed ports are being forwarded to Untangle or that Ut's IP is configured DMZ in the modem.

  5. #5
    Untangle Junkie dmorris's Avatar
    Join Date
    Nov 2006
    Location
    San Carlos, CA
    Posts
    17,747

    Default

    also it makes no sense that you have 192.168.0.2 on the external and 192.168.0.3 on the internal.
    this is not valid, and its is not even possible to save this configuration because they are the same subnet. Are you sure your internal isn't just bridged to your external?

    Or maybe you have different subnets and you are actually double NATing? If so, thats really gross and you should just run as a bridge.
    Attention: Support and help on the Untangle Forums is provided by volunteers and community members like yourself.
    If you need Untangle support please call or email support@untangle.com

  6. #6
    Untangler
    Join Date
    Nov 2016
    Location
    Grafton, Australia
    Posts
    39

    Default

    OK Thx for the suggestions. Will check these now.

    We have a very poor ADSL connection (1.1 mbps shared between 200 students & staff) so I need to avoid this doubling Nat'ing at all costs. Does anyone have any sample diagrams showing some indicative IP address across the modem and UT Ext / Int NICs ?

  7. #7
    Untangle Ninja jcoehoorn's Avatar
    Join Date
    Mar 2010
    Location
    York, NE
    Posts
    1,893

    Default

    Quote Originally Posted by dmorris View Post
    You need to configure port forwards on your modem.
    Or -- even better -- put the modem into bridge mode.
    Five time Microsoft ASP.Net MVP managing a Lenovo RD330 / E5-2420 / 16GB with Untangle 16.4.1 to protect 500Mbits for ~450 residential college students and associated staff and faculty

  8. #8
    Untangler
    Join Date
    Nov 2016
    Location
    Grafton, Australia
    Posts
    39

    Default

    OK Thx, we are all up & running again.
    I put the INT / EXT NICs on different networks, specified UT as a DMZ and put in port forwards for email & RDC.
    Users say it's the best speeds they seen for years, even wit this double NAT issue.
    Untangle_Setup.jpg
    Given there's been an outage, I'll plan on changing the router to bridge mode next week, in the normal change control window.

    So, when the router is in bridge mode, will the current IP adressing eliminate this double Nat ? Do I need to change anything in UT when I change the router to Bridge mode ?

  9. #9
    Untangle Ninja hescominsoon's Avatar
    Join Date
    Sep 2007
    Posts
    1,708

    Default

    if the adsl router is bridged it no longer gets an ip..it is just a modem..you will need to set your wan interface as per your isp guildelines(aka dhcp via either ethernet or if PPPOE is needed)...

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

SEO by vBSEO 3.6.0 PL2