$ sipcalc 203.196.171.124/28 -[ipv4 : 203.196.171.124/28] - 0 [CIDR] Host address - 203.196.171.124 Host address (decimal) - 3418663804 Host address (hex) - CBC4AB7C Network address - 203.196.171.112 Network mask - 255.255.255.240 Network mask (bits) - 28 Network mask (hex) - FFFFFFF0 Broadcast address - 203.196.171.127 Cisco wildcard - 0.0.0.15 Addresses in network - 16 Network range - 203.196.171.112 - 203.196.171.127 Usable range - 203.196.171.113 - 203.196.171.126
I think this is self explanatory. ;) I get reminded of this great Tamil saying my friend said: "Budhisaliku solli puriya veka vendiyathu illai, muttaluku sonnalum puriyathu" Have a good laugh. ;) It means this in Anglias. " It is pointless to make a fool understand: For the truly wise there is no need to explain." Anyway I will digress a bit and speak about mail servers. This IP address belongs to a company in TIDEL park HealthsoftUSA Pvt. Ltd. This is the way you figure out the mail server IP addresses(MX records) once you know the e-mail ID of your friend. Say you are sending mail to aplawrence.com. His ID is [email protected]. So Do a cut at the '@' character and take the domain part. Now, run dig on it with the '-t mx' switch. $ dig -t mx aplawrence.com ;; ANSWER SECTION: aplawrence.com. 7200 IN MX 10 aplawrence.com. Amidst all the noise in the output, this is what we want. There is aplawrence.com with a MX weight of 10. Now let us look at [email protected]. $ dig -t mx zoho.com ;; ANSWER SECTION: zoho.com. 1800 IN MX 10 mx.zohomail.com. zoho.com. 1800 IN MX 20 mx2.zohomail.com. zoho.com. 1800 IN MX 50 mx3.zohomail.com. We have three mail servers here. Now we want to figure out the IP addresses of each of them. You can easily find out either with a ping or dig again. $ dig mx.zohomail.com ;; ANSWER SECTION: mx.zohomail.com. 140 IN A 72.5.230.114 I got this from the noise. Now, the thing with static public IP addresses is that usually big companies/corporates buy a block of 16 IP addresses. So their mask will be this in most cases. 255.255.255.240 or /28. Then you want to know two things: a) which is the gateway in the upstream router of the ISP b) Which are the public IPs I can use for other purposes like HTTP, load balancing and so on sipcalc is useful for that. Sorry I want to digress little more now. You saw the zoho had three mail servers with MX weights 10, 20 and 50 respectively. This means that mails will be delivered with the record with weight 10 first. If that is busy,then the one with 20 and so on. Always priority in the technology world works this way. Lower the number, higher the priority. The idea of having multiple mail servers is to tell the mail server that sends mail that you can try contacting my backup mail server in case my primary mail server is busy or that the link is full or down. -Girish Gayatri Hitech web: http://gayatri-hitech.com SpamCheetah Spam filter: http://spam-cheetah.com _______________________________________________ To unsubscribe, email [email protected] with "unsubscribe <password> <address>" in the subject or body of the message. http://www.ae.iitm.ac.in/mailman/listinfo/ilugc
