[RndTbl] Shaw blocking port 25 on business line (Gerald Brandt)

Vijay Sankar vsankar at foretell.ca
Thu Jan 23 12:57:17 CST 2020


Hi,

Tried to simulate your situation on one of our Shaw Cable modems.  
FWIW, it looks to me like your firewall is probably using a DHCP  
address instead of the static address you may have configured.

Here is what I did and why I think you possibly could be using a DHCP  
address even though you are paying for static addresses. Hope the
following is helpful.

nps2245.foretell.ca# ifconfig em2
em2: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
	lladdr ob:fu:sc:at:ed:00
	index 3 priority 0 llprio 3
	groups: egress
	media: Ethernet autoselect (1000baseT full-
duplex,rxpause,txpause)
	status: active
	inet 184.71.76.158 netmask 0xfffffffc broadcast 184.71.76.159


nps2245.foretell.ca# telnet gmail-smtp-in.l.google.com 25
Trying 173.194.197.26...
Connected to gmail-smtp-in.l.google.com.
Escape character is '^]'.
220 mx.google.com ESMTP j12si2239041iok.52 - gsmtp
quit
221 2.0.0 closing connection j12si2239041iok.52 - gsmtp
Connection closed by foreign host.

nps2245.foretell.ca# dhclient em2
em2: 24.78.147.49 lease accepted from 24.78.144.1 (00:01:5c:88:aa:46)

nps2245.foretell.ca# telnet gmail-smtp-in.l.google.com 25
^C

SMTP does not work as you experienced, once I used a DHCP
address.reported

So set the interface back to the static address

nps2245.foretell.ca# sh /etc/netstart

nps2245.foretell.ca# ifconfig em2
em2: flags=808843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST,AUTOCONF4> mtu
1500
	lladdr ob:fu:sc:at:ed:00
	index 3 priority 0 llprio 3
	groups: egress
	media: Ethernet autoselect (1000baseT full-
duplex,rxpause,txpause)
	status: active
	inet 184.71.76.158 netmask 0xfffffffc broadcast 184.71.76.159

nps2245.foretell.ca# telnet gmail-smtp-in.l.google.com 25
Trying 74.125.142.27...
Connected to gmail-smtp-in.l.google.com.
Escape character is '^]'.
220 mx.google.com ESMTP g30si2236902pfr.206 - gsmtp
quit
221 2.0.0 closing connection g30si2236902pfr.206 - gsmtp
Connection closed by foreign host.

SMTP port accessible once the interface goes back to using static
addresses.

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> Today's Topics:
> 
>    1. Re: Shaw blocking port 25 on business line (Trevor Cordes)
>    2. Re: Shaw blocking port 25 on business line (Gerald Brandt)
>    3. Re: Shaw blocking port 25 on business line (
> athompso at athompso.net)
> 
> 
> -------------------------------------------------------------------
> ---
> 
> Message: 1
> Date: Thu, 23 Jan 2020 03:42:30 -0600
> From: Trevor Cordes <trevor at tecnopolis.ca>
> To: Gerald Brandt <gbr at majentis.com>
> Cc: Continuation of Round Table discussion <roundtable at muug.ca>
> Subject: Re: [RndTbl] Shaw blocking port 25 on business line
> Message-ID: <20200123034230.2af68ad8 at pog.tecnopolis.ca>
> Content-Type: text/plain; charset=US-ASCII
> 
> On 2020-01-21 Gerald Brandt wrote:
> > Hi,
> > 
> > I've been fighting with Shaw for days on this. I have what they
> > call
> > a business account with 8 static IPs.
> > 
> > I can telnet mail.shaw.ca 25 and get a connection. So, inside their
> > network, SMTP works.
> > 
> > If I try to telnet to any other server on port 25, i get no
> > connection. e.g. telnet to google email servers fails, telnet to my
> > server in Montreal fails.).
> 
> There is no reason your business account should have port 25 blocked,
> in either direction.  If they have done that to you, complain and get
> them to fix it.  If they gave you a static range, make sure you are
> using it and not grabbing one of their residential DHCP addresses by
> accident.
> 
> Also, the business side has some smart people working there, so
> there's
> no reason you shouldn't be able to get it resolved by people who
> understand your language.
> 
> I just checked and my customers on Shaw business have port 25
> outgoing
> unblocked.
> 
> 
> ------------------------------
> 
> Message: 2
> Date: Thu, 23 Jan 2020 07:49:28 -0600
> From: Gerald Brandt <gbr at majentis.com>
> To: Trevor Cordes <trevor at tecnopolis.ca>
> Cc: Continuation of Round Table discussion <roundtable at muug.ca>
> Subject: Re: [RndTbl] Shaw blocking port 25 on business line
> Message-ID: <11A03F6F-111F-4DA9-8A91-529665360579 at majentis.com>
> Content-Type: text/plain; charset="utf-8"
> 
> 
> 
> On January 23, 2020 3:42:30 a.m. CST, Trevor Cordes  
> <trevor at tecnopolis.ca> wrote:
> > On 2020-01-21 Gerald Brandt wrote:
> > > Hi,
> > > 
> > > I've been fighting with Shaw for days on this. I have what they
> > > call
> > > a business account with 8 static IPs.
> > > 
> > > I can telnet mail.shaw.ca 25 and get a connection. So, inside
> > > their
> > > network, SMTP works.
> > > 
> > > If I try to telnet to any other server on port 25, i get no
> > > connection. e.g. telnet to google email servers fails, telnet to
> > > my
> > > server in Montreal fails.).
> > 
> > There is no reason your business account should have port 25
> > blocked,
> > in either direction.  If they have done that to you, complain and
> > get
> > them to fix it.  If they gave you a static range, make sure you are
> > using it and not grabbing one of their residential DHCP addresses
> > by
> > accident.
> > 
> > Also, the business side has some smart people working there, so
> > there's
> > no reason you shouldn't be able to get it resolved by people who
> > understand your language.
> > 
> > I just checked and my customers on Shaw business have port 25
> > outgoing
> > unblocked.
> 
> I agree with everything you said, except the smart people comment.  
> If you tell me to login to my gmail account via web, and send and  
> email to myself (from gmail to gmail) and use the successful  
> delivery of the email as proof of port 25 being open, you have no  
> idea what you're talking about.
> 
> Guaranteed not using a DHCP address. Incoming port 25 works,  
> outgoing fails to leave their network.
> 
> The first person I talked to thought the 24.x.x x addresses they  
> gave me placed me in India. WTF?
> 
> Seven days, and this issue is still not resolved.
> 
> Gerald
> 
> --
> Sent from my Android device with K-9 Mail. Please excuse my brevity.
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> Message: 3
> Date: Thu, 23 Jan 2020 09:00:40 -0600
> From: athompso at athompso.net
> To: Continuation of Round Table discussion <roundtable at muug.ca>
> Subject: Re: [RndTbl] Shaw blocking port 25 on business line
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