SMPT connection fails for some network providers

[puspen]

I am getting SMTP connection problem for a GMAIL account in Mail.app
The mails never get sent and remain in outbox. This is the problem with my home wifi, but if I connect Mac to my Smartphone hotspot(Airtel network), the SMPT connects successful and emails gets sent.
Is it the problem related to my wifi Network Provider or the Mail app?
If it's the problem with Network provided, how the mails get sent from the browser, shouldn't there be some problem as well?

 

[matram]

Port 993 is for incoming mail using IMAP. SMTP for outgoing mail should be port 25 or 465. In my experience that would generally be another server. Are you sure about your config.

 

[puspen]

I tried all those ports. I had calls with Apple support but no use. But now I noticed that this issue comes only with my home wifi and not with my mobile hotspot.

 

[matram]

Most ISP where I come from (Sweden) would block at least port 25. Maybe you should call your ISP and verify that the ports are really open.

The ISP may provide their own SMTP server for you to use for your outgoing email. You can use any SMTP server for your this purpose, it does not have to be the imap server.

 

[puspen]

Most ISP where I come from (Sweden) would block at least port 25. Maybe you should call your ISP and verify that the ports are really open.

The ISP may provide their own SMTP server for you to use for your outgoing email. You can use any SMTP server for your this purpose, it does not have to be the imap server.

I asked my ISP to activate port 25 and they did, but still no luck.

 

[matram]

In general always start with verifying that you have a network connection to the port on the server and the server is responding on that port. Use this command in terminal:

nc -vz x.x.x.x 25

Replace x.x.x.x with the URL or IP-address of your SMTP server. You will get a response saying that the connection was successful, that it timed out (no connection) or was refused (server is not accepting calls on port 25).

 

[puspen]

Response I got : nc: connectx to Smtp.gmail.com port 25 (tcp) failed: Operation timed out
Ping is also failing with Request timeout for icmp_seq 1

 

[matram]

Just to confirm you should also do a ping smtp.gmail.com to verify that you have a network route to the server. If that shows you have a route, the nc results means that port 25 is blocked.

 

[puspen]

As I wrote in the previous reply, the ping to Smtp.gmail.com is failing with "Request timeout for icmp_seq 1" response.
Thanks for your help

 

[matram]

Oops, sorry missed that.

Missing route could mean a DNS issues. You could try with the IP adress, instead of the URL to verify that. You can see the IP adress below in my ping.

Here is my response:

mats@Mats-MBP ~ % ping smtp.gmail.com

PING smtp.gmail.com (173.194.73.109): 56 data bytes

64 bytes from 173.194.73.109: icmp_seq=0 ttl=43 time=24.179 ms

--- snip ---

mats@Mats-MBP ~ % nc smtp.gmail.com 25

220 ***********************************************

^C



The "220" message is the SMTP server saying OK, I am ready to receive your emails.



This is my response for a DNS lookup using dig, look in the answer section.

mats@Mats-MBP ~ % dig smtp.gmail.com

; <<>> DiG 9.10.6 <<>> smtp.gmail.com

;; global options: +cmd

;; Got answer:

;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 9260

;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1



;; OPT PSEUDOSECTION:

; EDNS: version: 0, flags:; udp: 4096

;; QUESTION SECTION:

;smtp.gmail.com. IN A



;; ANSWER SECTION:

smtp.gmail.com. 227 IN A 173.194.73.109



;; Query time: 33 msec

;; SERVER: 10.0.1.10#53(10.0.1.10)

;; WHEN: Sat Nov 16 11:44:02 CET 2019

;; MSG SIZE rcvd: 59

 

[puspen]

My ISP managed to configure the port correctly. It was their configs causing the issues. Now I can connect to SMTP on port 25. Thanks for your help, that helped me to guide my ISP's tech guy