use multiple ip addresses to tcp check remote server's port

Question

Im trying to tcp connect yahoo's mail server on port 25 . I have 3 public ip addresses lets say:-

(all are allowed in SPF records)
99.99.99.99
77.77.77.77
88.88.88.88

How to telnet(or other checks) using particular ip addresses to yahoos mta (check if all three of my ip addresses are allowed to send email to yahoo)

score 2 · Answer 1 · answered May 06 '17 at 16:01

2

According to the man page: -s sets the source IP address.

So you can do:

telnet -s 77.77.77.77 yahoo_mail_server 25

answered May 06 '17 at 16:01

Xavier Nicollet

1

for centos 6.7 with telnet-0.17-48.el6.x86_64. it has "-b" switch instead of "-s" – sherpaurgen May 06 '17 at 16:43

score 2 · Accepted Answer · answered May 06 '17 at 16:59

2

nc -s 77.77.77.77 -vz mta5.am0.yahoodns.net 25

OR

telnet -b 77.77.77.77 mta5.am0.yahoodns.net 25

answered May 06 '17 at 16:59

sherpaurgen

2 Answers2