Networking :: Getting Source Ip Address From Ip Header?

I have written C code to read data from the network using raw socket. I am printing out source/destination ip addresses and ports for packets I am interested in. For most part it decodes Source IP address correctly but sometimes the last part of the address is not correct. The destination ip address is always decoded correctly.

Here is the snippet of code:

Code:
struct sockaddr_in SenderAddr,Source,Dest;
socklen_t SenderLen = sizeof(SenderAddr);
struct iphdr *IpHdr;
struct udphdr *UdpHdr;

[Code]......