wireless router --> linux box & windows boxes Now, my linux box does NOT use dhcp, it has a fixed 192.168.x.x address. My windows box DOES use dhcp. The wireless router is the dhcp server too. tia gonz [allowsmilie] => 1 [showsignature] => 0 [ipaddress] => [iconid] => 0 [visible] => 1 [attach] => 0 [infraction] => 0 [reportthreadid] => 0 [isusenetpost] => 1 [msgid] => <6e79a637.0307221830.13bec8dd@posting.google.com> [ref] => [htmlstate] => on_nl2br [postusername] => Gonzo [ip] => gamazono@yahoo. [isdeleted] => 0 [usergroupid] => [membergroupids] => [displaygroupid] => [password] => [passworddate] => [email] => [styleid] => [parentemail] => [homepage] => [icq] => [aim] => [yahoo] => [msn] => [skype] => [showvbcode] => [showbirthday] => [usertitle] => [customtitle] => [joindate] => [daysprune] => [lastvisit] => [lastactivity] => [lastpost] => [lastpostid] => [posts] => [reputation] => [reputationlevelid] => [timezoneoffset] => [pmpopup] => [avatarid] => [avatarrevision] => [profilepicrevision] => [sigpicrevision] => [options] => [akvbghsfs_optionsfield] => [birthday] => [birthday_search] => [maxposts] => [startofweek] => [referrerid] => [languageid] => [emailstamp] => [threadedmode] => [autosubscribe] => [pmtotal] => [pmunread] => [salt] => [ipoints] => [infractions] => [warnings] => [infractiongroupids] => [infractiongroupid] => [adminoptions] => [profilevisits] => [friendcount] => [friendreqcount] => [vmunreadcount] => [vmmoderatedcount] => [socgroupinvitecount] => [socgroupreqcount] => [pcunreadcount] => [pcmoderatedcount] => [gmmoderatedcount] => [assetposthash] => [fbuserid] => [fbjoindate] => [fbname] => [logintype] => [fbaccesstoken] => [newrepcount] => [vbseo_likes_in] => [vbseo_likes_out] => [vbseo_likes_unread] => [temp] => [field1] => [field2] => [field3] => [field4] => [field5] => [subfolders] => [pmfolders] => [buddylist] => [ignorelist] => [signature] => [searchprefs] => [rank] => [icontitle] => [iconpath] => [avatarpath] => [hascustomavatar] => 0 [avatardateline] => [avwidth] => [avheight] => [edit_userid] => [edit_username] => [edit_dateline] => [edit_reason] => [hashistory] => [pagetext_html] => [hasimages] => [signatureparsed] => [sighasimages] => [sigpic] => [sigpicdateline] => [sigpicwidth] => [sigpicheight] => [postcount] => 1 [islastshown] => [isfirstshown] => 1 [attachments] => [allattachments] => ) --> wireless router --> linux box & windows[/quote] Uh ... you surely don't mnean wireless router, but wireless HUB. A basestation, no, attached to one of the sockets of the *cable modem and router*. [quote] > Now, my linux box does NOT use dhcp, it has a fixed 192.168.x.x > address.[/quote] Well, that's not going to even get out. That's a private address. You are going to have to set your cable modem router to do NAT to make the packets look like they are coming from its approved range - let's suppose it does that. Apparently it's picky about who it does it for, so you get to play with the cable modem router to tell it to pass more stuff out. [quote] > My windows box DOES use dhcp. The wireless router is the dhcp server > too.[/quote] No, the "cable modem router" is! The wireless basestation is just a hub. Talk to the wireless router .. there's no reason why it shouldn't do NAT for you if you ask it, and there's also no reason why you shouldn't allow yourself to get a local address by dhcp from it too. Peter [allowsmilie] => 1 [showsignature] => 0 [ipaddress] => [iconid] => 0 [visible] => 1 [attach] => 0 [infraction] => 0 [reportthreadid] => 0 [isusenetpost] => 1 [msgid] => [ref] => <6e79a637.0307221830.13bec8dd@posting.google.com> [htmlstate] => on_nl2br [postusername] => Peter T. 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A > basestation, no, attached to one of the sockets of the *cable modem > and router*.[/quote] Not to be contrary but it is a wireless router. A hub is a shared network device that only connects devices on the _same_ network. A router, which this is, routes traffic from one network to another network, which this does. The wireless router has TWO IP addresses, in this case one is the IP address for the wan (via the cable modem), the other IP address is for my lan (in this case a 192.168.x.x address). Then computers on one side of the router can speak with computers on the other side of the router. It also does NAT, so that my lan side can be non-routable IP addresses and all go out looking as if they came from the routable address given to me by my ISP. I'm not real sure about the inner workings of cable modems or the ISP's network, but I'm pretty sure that the cable modem is not a router. It allows ONE routable IP address through it's ONE port. It seems to be just a dhcp enabled device on their network. It certainly does NOT seem to route traffic. Meaning, I can't hook up a hub or switch to it and have it as my gateway to route other traffic. I may be wrong on that point though. Irregardless though, this wireless device of mine is a router which routes traffic from my 192.x side to the ISP side of the network. [quote] >[quote] > > Now, my linux box does NOT use dhcp, it has a fixed 192.168.x.x > > address.[/quote] > > Well, that's not going to even get out. That's a private address. > You are going to have to set your cable modem router to do NAT > to make the packets look like they are coming from its approved > range - let's suppose it does that. Apparently it's picky about who it > does it for, so you get to play with the cable modem router to > tell it to pass more stuff out.[/quote] The wireless router does do NAT. And it handles it fine. My linux box has no problems doing anything else that I need. I *can* telnet from the linux box to other machines, including port 25 on another smtp server. The problem is that other smtp server can't be used (it won't send outside of its domain). So the smtp server that I need to use, I can't connect to port on 25 from my linux box (even though I *can* connect to it from a windows box that's on the same internal network). [quote] >[quote] > > My windows box DOES use dhcp. The wireless router is the dhcp server > > too.[/quote] > > No, the "cable modem router" is! The wireless basestation is just a > hub. Talk to the wireless router .. there's no reason why it shouldn't > do NAT for you if you ask it, and there's also no reason why you > shouldn't allow yourself to get a local address by dhcp from it too.[/quote] The wireless thingy really is a router, not a hub. It does do NAT. I *could* get an address from it using DHCP, but since I allow my wireless router to route inbound ssh traffic to my linux box, the linux box needs a fixed address. [allowsmilie] => 1 [showsignature] => 0 [ipaddress] => [iconid] => 0 [visible] => 1 [attach] => 0 [infraction] => 0 [reportthreadid] => 0 [isusenetpost] => 1 [msgid] => <6e79a637.0307230713.492d2a91@posting.google.com> [ref] => <6e79a637.0307221830.13bec8dd@posting.google.com> [htmlstate] => on_nl2br [postusername] => Gonzo [ip] => gamazono@yahoo. 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A >> basestation, no, attached to one of the sockets of the *cable modem >> and router*.[/quote][/quote] [quote] > Not to be contrary but it is a wireless router. A hub is a shared > network device that only connects devices on the _same_ network. A[/quote] That's correct. [quote] > router, which this is, routes traffic from one network to another > network, which this does. The wireless router has TWO IP addresses, in > this case one is the IP address for the wan (via the cable modem), the[/quote] The cable modem will normally have a WAN address and a localnet address and will be the router between yoru intranet and your ISPs intranet. [quote] > other IP address is for my lan (in this case a 192.168.x.x address). > Then computers on one side of the router can speak with computers on > the other side of the router. It also does NAT, so that my lan side > can be non-routable IP addresses and all go out looking as if they > came from the routable address given to me by my ISP.[/quote] What you are saying is that the cable modem is a hub and the wireless station is the router. That the cable modem is not a router is nigh on incredible. Maybe they exist. I've not seen one. I can imagine one - it would be a terminal device, essentially, an extension of your isp's net. [quote] > I'm not real sure about the inner workings of cable modems or the > ISP's network, but I'm pretty sure that the cable modem is not a > router. It allows ONE routable IP address through it's ONE port. It[/quote] That's exactly right. It normally has an external WAN address (the cable side), and it routes between that and the port(s) on the internal net side. It usually does NAT translation for the intranet, but you can configure it any which way. [quote] > seems to be just a dhcp enabled device on their network. It certainly > does NOT seem to route traffic. Meaning, I can't hook up a hub or[/quote] It normally would if you configured it to do so. As I said, it normally does NAT translation from an intranet. A more convenient way to set it up is as a port forwarder, however, for a chosen machine on your intranet. That machine then acts as your gateway. [quote] > switch to it and have it as my gateway to route other traffic. I may[/quote] You normally should be able to! [quote] > be wrong on that point though. Irregardless though, this wireless > device of mine is a router which routes traffic from my 192.x side to > the ISP side of the network.[/quote] Well, what's its ISP side address? How have you managed to get two addresses out of your ISP? One for the cable modem and one for your router? [quote][quote][quote] >> > Now, my linux box does NOT use dhcp, it has a fixed 192.168.x.x >> > address.[/quote] >> >> Well, that's not going to even get out. That's a private address. >> You are going to have to set your cable modem router to do NAT >> to make the packets look like they are coming from its approved >> range - let's suppose it does that. Apparently it's picky about who it >> does it for, so you get to play with the cable modem router to >> tell it to pass more stuff out.[/quote][/quote] [quote] > The wireless router does do NAT. And it handles it fine. My linux box > has no problems doing anything else that I need. I *can* telnet from > the linux box to other machines, including port 25 on another smtp > server.[/quote] Then outgoing 25 is not firewalled by you or your router, but incoming 25 from you is firewalled by your ISP. That is hard to imagine. [quote] > The problem is that other smtp server can't be used (it won't send > outside of its domain). So the smtp server that I need to use, I can't > connect to port on 25 from my linux box (even though I *can* connect[/quote] Please run tcpdump while making the connection. Compare with the dump when doing it from windows. [quote] > to it from a windows box that's on the same internal network).[/quote] [quote][quote][quote] >> > My windows box DOES use dhcp. The wireless router is the dhcp server >> > too.[/quote] >> >> No, the "cable modem router" is! The wireless basestation is just a >> hub. Talk to the wireless router .. there's no reason why it shouldn't >> do NAT for you if you ask it, and there's also no reason why you >> shouldn't allow yourself to get a local address by dhcp from it too.[/quote][/quote] [quote] > The wireless thingy really is a router, not a hub.[/quote] [quote] > It does do NAT. I *could* get an address from it using DHCP, but since > I allow my wireless router to route inbound ssh traffic to my linux > box, the linux box needs a fixed address.[/quote] Peter [allowsmilie] => 1 [showsignature] => 0 [ipaddress] => [iconid] => 0 [visible] => 1 [attach] => 0 [infraction] => 0 [reportthreadid] => 0 [isusenetpost] => 1 [msgid] => [ref] => <6e79a637.0307221830.13bec8dd@posting.google.com> <6e79a637.0307230713.492d2a91@posting.google.com> [htmlstate] => on_nl2br [postusername] => Peter T. 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HELP: Linux telnet smtp server fails, Works from MS Windows - Linux Setup, Configuration & Administration

I'm stumped. And I'm not a guru. I think I have a network setup problem on my Linux box, but I'm not sure what to look for. Problem: Trying to get sendmail working. On linux box, cannot telnet to my ISP's smtp server. What I've tried: From linux box: telnet my-isp-smtp-server 25 I get: telnet: Unable to connect to remote host: Connection refused I can ping it fine though. From my windows box, when I try the same telnet, it works fine and I can do a manual email out, and it gets delivered fine. Any help would be greatly ...

  1. #1

    Default HELP: Linux telnet smtp server fails, Works from MS Windows

    I'm stumped. And I'm not a guru.

    I think I have a network setup problem on my Linux box, but I'm not
    sure what to look for.

    Problem:
    Trying to get sendmail working. On linux box, cannot telnet to my
    ISP's smtp server.

    What I've tried:
    From linux box: telnet my-isp-smtp-server 25
    I get: telnet: Unable to connect to remote host: Connection refused
    I can ping it fine though.

    From my windows box, when I try the same telnet, it works fine and I
    can do a manual email out, and it gets delivered fine.

    Any help would be greatly appreciated. I've been working on it for a
    few evenings now, and I'm out of ideas.

    Here's my network setup, just in case:
    RoadRunner cable modem --> wireless router --> linux box & windows
    boxes
    Now, my linux box does NOT use dhcp, it has a fixed 192.168.x.x
    address.
    My windows box DOES use dhcp. The wireless router is the dhcp server
    too.

    tia
    gonz
    Gonzo Guest

  2. #2

    Default Re: HELP: Linux telnet smtp server fails, Works from MS Windows

    Gonzo <gamazono> wrote:
    > Trying to get sendmail working. On linux box, cannot telnet to my
    > ISP's smtp server.
    Then you have a firewall up on port 25 outgoing. Take it away.
    Either that or they have one up and you are sending from a wrong IP
    address to get through.
    > From linux box: telnet my-isp-smtp-server 25
    > I get: telnet: Unable to connect to remote host: Connection refused
    Well, refused is a bit strong ...
    > I can ping it fine though.
    But not on port 25!
    > From my windows box, when I try the same telnet, it works fine and I
    > can do a manual email out, and it gets delivered fine.
    > Any help would be greatly appreciated. I've been working on it for a
    > few evenings now, and I'm out of ideas.
    THe first idea you should have would be to tell us about your
    networking.
    > Here's my network setup, just in case:
    "in case"?
    > RoadRunner cable modem --> wireless router --> linux box & windows
    Uh ... you surely don't mnean wireless router, but wireless HUB. A
    basestation, no, attached to one of the sockets of the *cable modem
    and router*.
    > Now, my linux box does NOT use dhcp, it has a fixed 192.168.x.x
    > address.
    Well, that's not going to even get out. That's a private address.
    You are going to have to set your cable modem router to do NAT
    to make the packets look like they are coming from its approved
    range - let's suppose it does that. Apparently it's picky about who it
    does it for, so you get to play with the cable modem router to
    tell it to pass more stuff out.
    > My windows box DOES use dhcp. The wireless router is the dhcp server
    > too.
    No, the "cable modem router" is! The wireless basestation is just a
    hub. Talk to the wireless router .. there's no reason why it shouldn't
    do NAT for you if you ask it, and there's also no reason why you
    shouldn't allow yourself to get a local address by dhcp from it too.

    Peter
    Peter T. Breuer Guest

  3. #3

    Default Re: HELP: Linux telnet smtp server fails, Works from MS Windows

    "Peter T. Breuer" <ptboboe.it.uc3m.es> wrote in message news:<jlhlfb.7cg.lnnews.it.uc3m.es>...
    > Gonzo <gamazono> wrote:
    > > Trying to get sendmail working. On linux box, cannot telnet to my
    > > ISP's smtp server.
    >
    > Then you have a firewall up on port 25 outgoing. Take it away.
    > Either that or they have one up and you are sending from a wrong IP
    > address to get through.
    I'm not sure that's it. I think it may be something else with my
    network setup on my Linux box. If it is a firewall thing, it must be
    on the linux box itself. Any suggestions where I should look there?
    Since it works from a windows box on the same LAN, it's *not* the
    wireless router (or it's firewall).
    >
    > > From linux box: telnet my-isp-smtp-server 25
    > > I get: telnet: Unable to connect to remote host: Connection refused
    >
    > Well, refused is a bit strong ...
    >
    > > I can ping it fine though.
    >
    > But not on port 25!
    Obviously, since 25 is talking SMTP. The point being that the linux
    box CAN see the the smtp server and can translate the name to it's IP
    address.
    >
    > > From my windows box, when I try the same telnet, it works fine and I
    > > can do a manual email out, and it gets delivered fine.
    >
    > > Any help would be greatly appreciated. I've been working on it for a
    > > few evenings now, and I'm out of ideas.
    >
    > THe first idea you should have would be to tell us about your
    > networking.
    >
    > > Here's my network setup, just in case:
    >
    > "in case"?
    >
    > > RoadRunner cable modem --> wireless router --> linux box & windows
    >
    > Uh ... you surely don't mnean wireless router, but wireless HUB. A
    > basestation, no, attached to one of the sockets of the *cable modem
    > and router*.
    Not to be contrary but it is a wireless router. A hub is a shared
    network device that only connects devices on the _same_ network. A
    router, which this is, routes traffic from one network to another
    network, which this does. The wireless router has TWO IP addresses, in
    this case one is the IP address for the wan (via the cable modem), the
    other IP address is for my lan (in this case a 192.168.x.x address).
    Then computers on one side of the router can speak with computers on
    the other side of the router. It also does NAT, so that my lan side
    can be non-routable IP addresses and all go out looking as if they
    came from the routable address given to me by my ISP.

    I'm not real sure about the inner workings of cable modems or the
    ISP's network, but I'm pretty sure that the cable modem is not a
    router. It allows ONE routable IP address through it's ONE port. It
    seems to be just a dhcp enabled device on their network. It certainly
    does NOT seem to route traffic. Meaning, I can't hook up a hub or
    switch to it and have it as my gateway to route other traffic. I may
    be wrong on that point though. Irregardless though, this wireless
    device of mine is a router which routes traffic from my 192.x side to
    the ISP side of the network.
    >
    > > Now, my linux box does NOT use dhcp, it has a fixed 192.168.x.x
    > > address.
    >
    > Well, that's not going to even get out. That's a private address.
    > You are going to have to set your cable modem router to do NAT
    > to make the packets look like they are coming from its approved
    > range - let's suppose it does that. Apparently it's picky about who it
    > does it for, so you get to play with the cable modem router to
    > tell it to pass more stuff out.
    The wireless router does do NAT. And it handles it fine. My linux box
    has no problems doing anything else that I need. I *can* telnet from
    the linux box to other machines, including port 25 on another smtp
    server.

    The problem is that other smtp server can't be used (it won't send
    outside of its domain). So the smtp server that I need to use, I can't
    connect to port on 25 from my linux box (even though I *can* connect
    to it from a windows box that's on the same internal network).

    >
    > > My windows box DOES use dhcp. The wireless router is the dhcp server
    > > too.
    >
    > No, the "cable modem router" is! The wireless basestation is just a
    > hub. Talk to the wireless router .. there's no reason why it shouldn't
    > do NAT for you if you ask it, and there's also no reason why you
    > shouldn't allow yourself to get a local address by dhcp from it too.
    The wireless thingy really is a router, not a hub.

    It does do NAT. I *could* get an address from it using DHCP, but since
    I allow my wireless router to route inbound ssh traffic to my linux
    box, the linux box needs a fixed address.
    Gonzo Guest

  4. #4

    Default Re: HELP: Linux telnet smtp server fails, Works from MS Windows

    Gonzo <gamazono> wrote:
    > "Peter T. Breuer" <ptboboe.it.uc3m.es> wrote in message news:<jlhlfb.7cg.lnnews.it.uc3m.es>...
    >> Gonzo <gamazono> wrote:
    >> > Trying to get sendmail working. On linux box, cannot telnet to my
    >> > ISP's smtp server.
    >>
    >> Then you have a firewall up on port 25 outgoing. Take it away.
    >> Either that or they have one up and you are sending from a wrong IP
    >> address to get through.
    > I'm not sure that's it. I think it may be something else with my
    No it isn't - unless your routing is wrong, and you PROVED it is not
    wrong by pinging successfully. Therefore it is what I said.
    > network setup on my Linux box. If it is a firewall thing, it must be
    > on the linux box itself. Any suggestions where I should look there?
    At the firewall. But please PAY ATTENTION to what I say. The
    indication is that the oruter is firewalling or not doing NAT for you.
    > Since it works from a windows box on the same LAN, it's *not* the
    > wireless router (or it's firewall).
    Nonsense. What kind of misbegotten thinking causes you that brain?
    The windows box has gotten its IP by dhcp, so will certainly have had a
    hole in the firewall opened for it by the router. Something stopping
    you looking at the routers firewall?
    >> > From linux box: telnet my-isp-smtp-server 25
    >> > I get: telnet: Unable to connect to remote host: Connection refused
    >>
    >> Well, refused is a bit strong ...
    >>
    >> > I can ping it fine though.
    >>
    >> But not on port 25!
    > Obviously, since 25 is talking SMTP. The point being that the linux
    > box CAN see the the smtp server and can translate the name to it's IP
    > address.
    But it can't talk on port 25, therefore

    Then you have a firewall up on port 25 outgoing.
    Either that or they have one up and you are sending from a wrong IP
    address to get through.

    >> THe first idea you should have would be to tell us about your
    >> networking.
    >>
    >> > Here's my network setup, just in case:
    >>
    >> "in case"?
    >>
    >> > RoadRunner cable modem --> wireless router --> linux box & windows
    >>
    >> Uh ... you surely don't mnean wireless router, but wireless HUB. A
    >> basestation, no, attached to one of the sockets of the *cable modem
    >> and router*.
    > Not to be contrary but it is a wireless router. A hub is a shared
    > network device that only connects devices on the _same_ network. A
    That's correct.
    > router, which this is, routes traffic from one network to another
    > network, which this does. The wireless router has TWO IP addresses, in
    > this case one is the IP address for the wan (via the cable modem), the
    The cable modem will normally have a WAN address and a localnet
    address and will be the router between yoru intranet and your ISPs
    intranet.
    > other IP address is for my lan (in this case a 192.168.x.x address).
    > Then computers on one side of the router can speak with computers on
    > the other side of the router. It also does NAT, so that my lan side
    > can be non-routable IP addresses and all go out looking as if they
    > came from the routable address given to me by my ISP.
    What you are saying is that the cable modem is a hub and the wireless
    station is the router. That the cable modem is not a router is nigh on
    incredible. Maybe they exist. I've not seen one. I can imagine one - it
    would be a terminal device, essentially, an extension of your isp's
    net.
    > I'm not real sure about the inner workings of cable modems or the
    > ISP's network, but I'm pretty sure that the cable modem is not a
    > router. It allows ONE routable IP address through it's ONE port. It
    That's exactly right. It normally has an external WAN address (the
    cable side), and it routes between that and the port(s) on the internal
    net side. It usually does NAT translation for the intranet, but you can
    configure it any which way.
    > seems to be just a dhcp enabled device on their network. It certainly
    > does NOT seem to route traffic. Meaning, I can't hook up a hub or
    It normally would if you configured it to do so. As I said, it normally
    does NAT translation from an intranet. A more convenient way to set it
    up is as a port forwarder, however, for a chosen machine on your
    intranet. That machine then acts as your gateway.
    > switch to it and have it as my gateway to route other traffic. I may
    You normally should be able to!
    > be wrong on that point though. Irregardless though, this wireless
    > device of mine is a router which routes traffic from my 192.x side to
    > the ISP side of the network.
    Well, what's its ISP side address? How have you managed to get two
    addresses out of your ISP? One for the cable modem and one for your
    router?

    >> > Now, my linux box does NOT use dhcp, it has a fixed 192.168.x.x
    >> > address.
    >>
    >> Well, that's not going to even get out. That's a private address.
    >> You are going to have to set your cable modem router to do NAT
    >> to make the packets look like they are coming from its approved
    >> range - let's suppose it does that. Apparently it's picky about who it
    >> does it for, so you get to play with the cable modem router to
    >> tell it to pass more stuff out.
    > The wireless router does do NAT. And it handles it fine. My linux box
    > has no problems doing anything else that I need. I *can* telnet from
    > the linux box to other machines, including port 25 on another smtp
    > server.
    Then outgoing 25 is not firewalled by you or your router, but incoming
    25 from you is firewalled by your ISP. That is hard to imagine.
    > The problem is that other smtp server can't be used (it won't send
    > outside of its domain). So the smtp server that I need to use, I can't
    > connect to port on 25 from my linux box (even though I *can* connect
    Please run tcpdump while making the connection. Compare with the dump
    when doing it from windows.
    > to it from a windows box that's on the same internal network).
    >> > My windows box DOES use dhcp. The wireless router is the dhcp server
    >> > too.
    >>
    >> No, the "cable modem router" is! The wireless basestation is just a
    >> hub. Talk to the wireless router .. there's no reason why it shouldn't
    >> do NAT for you if you ask it, and there's also no reason why you
    >> shouldn't allow yourself to get a local address by dhcp from it too.
    > The wireless thingy really is a router, not a hub.
    > It does do NAT. I *could* get an address from it using DHCP, but since
    > I allow my wireless router to route inbound ssh traffic to my linux
    > box, the linux box needs a fixed address.
    Peter
    Peter T. Breuer Guest

  5. #5

    Default Re: HELP: Linux telnet smtp server fails, Works from MS Windows

    Peter, first I would like to say that I do appreciate your attempt to
    help. However your tone leaves a lot to be desired. There's really no
    reason to talk down to people asking questions. Many intelligent
    people have been known to ask questions. Questions further ones grasp
    of the world around them.

    "Peter T. Breuer" <ptboboe.it.uc3m.es> wrote in message news:<ombmfb.sk.lnnews.it.uc3m.es>...

    [much snipped, see thread]
    >
    > At the firewall. But please PAY ATTENTION to what I say. The
    > indication is that the oruter is firewalling or not doing NAT for you.
    I'm paying quite a bit of attention, thank you.

    The router/firewall is not blocking port 25, and it IS doing NAT. I've
    mentioned this all before.

    I tend to think it's a linux issue (thus the reason for posting to
    comp.os.linux.setup) because I have another computer (a windows box)
    on the SAME network and that computer has no problem telneting to port
    25 of the ISPs smtp server.

    The linux box can PING the smtp server. PING doesn't work over port 25
    so it's quite obvious that ping doesn't talk to the smtp server on
    port 25. That's a given. The point is that the linux box *can* see the
    smtp server, it just cannot talk to port 25 of that server. That is a
    critical thing. If the linux box couldn't ping the server, I would
    have to look in a different direction for the answer.

    The linux box can also telnet out to many many boxes. AND it can
    telnet to port 25 on other smtp servers. Those "other" servers that
    can telneted to can not be used because they don't do relays (only
    mail within the domain).

    So bottom line is I'm pretty sure that it's something in my linux
    setup. And I'm starting to think it something about the way I have my
    liunx host name/domain name configured.
    >
    > > Since it works from a windows box on the same LAN, it's *not* the
    > > wireless router (or it's firewall).
    >
    > Nonsense. What kind of misbegotten thinking causes you that brain?
    > The windows box has gotten its IP by dhcp, so will certainly have had a
    > hole in the firewall opened for it by the router. Something stopping
    > you looking at the routers firewall?
    Getting an IP address from dhcp does NOT open holes in your firewall.
    That would be a bad thing. DHCP is not magical. It's simply a method
    of providing IP addresses (and a few other setup things) to a host. It
    doesn't do any further magic on behalf of the host.

    As mentioned, I've looked at the firewall built into my router. It's
    not there. That firewall lets the traffic pass. I can get to port 25
    from the windows box. And I can get to other servers port 25 from my
    linux box, just not the one I need to get to.


    [more deleted...]
    >
    > The cable modem will normally have a WAN address and a localnet
    > address and will be the router between yoru intranet and your ISPs
    > intranet.
    [stuff deleted]
    > What you are saying is that the cable modem is a hub and the wireless
    > station is the router. That the cable modem is not a router is nigh on
    > incredible. Maybe they exist. I've not seen one. I can imagine one - it
    > would be a terminal device, essentially, an extension of your isp's
    > net.
    >
    > It normally would if you configured it to do so. As I said, it normally
    > does NAT translation from an intranet. A more convenient way to set it
    > up is as a port forwarder, however, for a chosen machine on your
    > intranet. That machine then acts as your gateway.
    This cable modem issue is a little off topic, but since we got here I
    would like to help you to understand them a little more.

    The cable modem does NOT do routing. One could not take a computer
    with say a 192.168.x.x IP address, set it up to use the cable modems
    IP address as the gateway and expect the traffic to be routed between
    the two networks.

    I admit, I am not an expert on HOW they work but they seem to be
    bridges. Meaning IP addresses on *both* sides of the device are on the
    same network. They don't route. They don't do NAT. They seem to just
    bridge traffic at the MAC layer.

    So, if one wants to set up an internal network, and have that network
    communicate with the ISPs network, one would need a router on the
    inside of the cable modem to route traffic from the internal network
    to the ISP's network. NAT is needed because on my internal network,
    I've decided to use 192.168.x.x addresses which are reserved (for
    situations just like mine) and are not routable IP addresses. So for
    my 192.168.x.x traffic to go out over the internet, NAT is needed to
    make it seem like that traffic came from a routable IP address.

    If you'd like to know more about the subject of cable modems you can
    read about them here:

    [url]http://computer.howstuffworks.com/framed.htm?parent=cable-modem.htm&url=http://www.cable-modems.org/tutorial/[/url]
    Gonzo Guest

  6. #6

    Default Re: HELP: Linux telnet smtp server fails, Works from MS Windows

    Gonzo wrote:
    > I'm stumped. And I'm not a guru.
    >
    > I think I have a network setup problem on my Linux box, but I'm not
    > sure what to look for.
    >
    > Problem:
    > Trying to get sendmail working. On linux box, cannot telnet to my
    > ISP's smtp server.
    >
    > What I've tried:
    > From linux box: telnet my-isp-smtp-server 25
    > I get: telnet: Unable to connect to remote host: Connection refused
    > I can ping it fine though.
    Just a guess, but could the ISP actually be running a proxy of sorts.
    Are you able to do a telent my-isp-smtp-server 25 from Windows?
    (just asking about doing a regular telnet, not relying on your MUA).

    Chris Cox Guest

  7. #7

    Default Re: HELP: Linux telnet smtp server fails, Works from MS Windows

    Gonzo <gamazono> wrote:
    > Peter, first I would like to say that I do appreciate your attempt to
    > help. However your tone leaves a lot to be desired. There's really no
    Tone is what YOU read, not what I write. Amend the way you read and all
    will be well.
    > "Peter T. Breuer" <ptboboe.it.uc3m.es> wrote in message news:<ombmfb.sk.lnnews.it.uc3m.es>...
    > The router/firewall is not blocking port 25, and it IS doing NAT. I've
    > mentioned this all before.
    You have proved that there is a firewall blocking port 25. Why do you
    assert that it is not the router?
    > I tend to think it's a linux issue (thus the reason for posting to
    You proved that there is no routing problem by pinging. The firewall
    can be anywhere, including on the linux box.
    > The linux box can also telnet out to many many boxes. AND it can
    > telnet to port 25 on other smtp servers. Those "other" servers that
    That proves (mostly) that the firewall is not on the linux box.
    > So bottom line is I'm pretty sure that it's something in my linux
    Curious deduction.
    > setup. And I'm starting to think it something about the way I have my
    > liunx host name/domain name configured.
    They generally must be resolvable by reverse dns on the receiving server
    if it is to accept mail from you, but it will respond to telnet on port
    25 in order to see who you say you are!
    >> > Since it works from a windows box on the same LAN, it's *not* the
    >> > wireless router (or it's firewall).
    >>
    >> Nonsense. What kind of misbegotten thinking causes you that brain?
    >> The windows box has gotten its IP by dhcp, so will certainly have had a
    >> hole in the firewall opened for it by the router. Something stopping
    >> you looking at the routers firewall?
    > Getting an IP address from dhcp does NOT open holes in your firewall.
    It should do.
    > That would be a bad thing. DHCP is not magical. It's simply a method
    You don't understand ... the dhcp service normally is linked to other
    services, such as DNS and a firewall. Yes, getting an IP by dhcp from a
    dhcp server normally will cause other effects.
    > of providing IP addresses (and a few other setup things) to a host. It
    > doesn't do any further magic on behalf of the host.
    Oh yes it does.

    Peter
    Peter T. Breuer Guest

  8. #8

    Default Re: HELP: Linux telnet smtp server fails, Works from MS Windows

    Peter,

    First, to actually hint that one cannot infer tone by reading is
    absolutely ridiculous. If one could not convey tone in the written
    language, many novelists would be out of work. That's just absurd.
    Certainly one can convey tone through writing.

    Second, when one writes something like:
    "What kind of misbegotten thinking causes you that brain?"
    (a quote from you btw) it's obvious that you are talking down to
    someone.

    Third, your understanding of DHCP and networking does not appear to be
    up to par. I could be mistaken; I don't know you nor your background.
    But in our brief discussion, you have been incorrect on a few points.

    Finally, if you don't want to help people, don't. No since being rude
    to people asking questions. Everyone that asks a question isn't
    stupid, usually quite the opposite. If someone asking a question puts
    you in a bad mood, just don't reply.

    Have a good life...

    gonzo
    Gonzo Guest

  9. #9

    Default Re: HELP: Linux telnet smtp server fails, Works from MS Windows

    Chris Cox <ccox_nopenotthisairmail.net> wrote in message news:<bfpmkm$seolibrary1.airnews.net>...
    > Gonzo wrote:
    [deleted]
    >
    > Just a guess, but could the ISP actually be running a proxy of sorts.
    > Are you able to do a telent my-isp-smtp-server 25 from Windows?
    > (just asking about doing a regular telnet, not relying on your MUA).
    Yeah, actually, I can get to it from my windows box on the same lan.
    And my linux box can actually get to other servers on port 25, just
    not this one that I need to get to. (The others don't relay outside of
    the domain, so that's why I can't use them, but I CAN get to port 25
    on them from this linux box.)

    I think it has something to do with where the smtp-server thinks my
    linux box domain is or something. For some reason it must not think
    that this linux box is in the domain. I looked at my linux setup
    though and it looks ok to me, but I could easily be missing something.
    Gonzo Guest

  10. #10

    Default Re: HELP: Linux telnet smtp server fails, Works from MS Windows

    Gonzo <gamazono> wrote:
    > First, to actually hint that one cannot infer tone by reading is
    > absolutely ridiculous.
    I'm sorry - you really can't! It's well known that ascii does not
    convey tone, that shakespeare's plays have completely opposed readings,
    etc. . That's why people invented emoticons (smileys).
    > If one could not convey tone in the written
    > language, many novelists would be out of work.
    On the contrary, you can't convey it, and they're not out of work.
    > Certainly one can convey tone through writing.
    No one can't.
    > Second, when one writes something like:
    > "What kind of misbegotten thinking causes you that brain?"
    > (a quote from you btw) it's obvious that you are talking down to
    > someone.
    Uhm no. What makes you think that? I'm being friendly. I'm treating you
    as an equal.
    > Third, your understanding of DHCP and networking does not appear to be
    Tut tut. I'm afraid it is. Among other things I run the network here,
    including dhccp and dns. I wrote the dyndns scripts. And I won't
    mention I've taught all this sort of stuff for many years ;).
    > up to par. I could be mistaken; I don't know you nor your background.
    Then perhaps you might consider that there are other things that you
    can't tell from ascii. Surprising, isn't it!
    > But in our brief discussion, you have been incorrect on a few points.
    No, I haven't. That you think so is something you should take into
    consideration. After all, you are also not able to correct your
    problem.
    > Finally, if you don't want to help people, don't. No since being rude
    Well, well. OK. I won't. Deal.

    You can just keep on walking ronund with the old nose in the air, thinking
    that people are talking down to you.
    > to people asking questions. Everyone that asks a question isn't
    > stupid, usually quite the opposite. If someone asking a question puts
    > you in a bad mood, just don't reply.
    Why? Can't you take criticism? Or is it contradiction, etc. etc.
    > Have a good life...
    > gonzo
    What a gonzo!

    Peter
    Peter T. Breuer Guest

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