Dnsseed not listening on port 53 and does not throw any error

We need to setup dnsseed (Seeder for litecoin cloned altcoin).

Software which we tried

There are no errors during compiling and make. but after compiled, It does not listen on any port.
as a debug process, we installed bind9 and bind9 works fine with same DNS settings.

Issue1: dnsseed does not listen on port (any port specified)
issue2: dnsseed does not throw any error even if assigned to run on already used port.
Issue3: There are no logs about any thing happening in dnsseed. (error, info etc)

Start Command

./dnsseed -h seeder.ourdomain.com -n 999.99.999.9 -m [email protected] -p 53

999.99.999.9 is given as example of our Server IP on which seeder is running

Output

Loading dnsseed.dat…done
Starting 4 DNS threads for seeder.domain.com on 999.99.999.9 (port 53)…done
Starting seeder…done
Starting 96 crawler threads…done
[20-03-11 17:27:23] 639/16822 available (13340 tried in 79030s, 1946 new, 1536 active), 1 banned; 0 DNS requ ests, 0 db queries
Supporting whitelisted filters: 0x1,0x5,0x9,0xd
Loading dnsseed.dat…done
Starting 4 DNS threads for seeder.domain.com on 999.99.999.9 (port 53)…done
Starting seeder…done
Starting 96 crawler threads…done

But
netstat -tulpn

does not list port 53 being listened and server does not respond on port 53 requests.

Any possible solution to this?
Thanks in advance.