I tried to boot by pxeboot using some Linux nfs servers. But, I could not boot by using Linux nfs servers. I tested using CentOS6.7 and CentOS7.1 as a dhcp,tftp,NFS server. The pxeboot of FreeBSD9.3 and 10.2 correctly downloaded by TFTP from Linux server. At second stage , the pxeboot will mount to load kernel by nfs. But, pxeboot was failed to mount nfs. I monitored a packet using tcpdump. It was as below. 14:12:47.658036 IP 192.168.8.215.1023 > 192.168.8.2.sunrpc: UDP,length 76 14:12:47.658349 IP 192.168.8.2.sunrpc > 192.168.8.215.1023: UDP,length 28 ... reapeat infinity .... I checked a source file of pxeboot at FreeBSD 9.3, then I was succeed to boot using Linux NFS Server. My improvement is as below. *** /sys/boot/i386/libi386/pxe.c.orig 2014-12-14 13:47:38.000000000 +0900 --- /sys/boot/i386/libi386/pxe.c 2016-04-10 20:24:13.000000000 +0900 *************** *** 673,679 **** uh = (struct udphdr *) pkt - 1; bzero(udpread_p, sizeof(*udpread_p)); ! udpread_p->dest_ip = h->myip.s_addr; udpread_p->d_port = h->myport; udpread_p->buffer_size = len; udpread_p->buffer.segment = VTOPSEG(data_buffer); --- 673,679 ---- uh = (struct udphdr *) pkt - 1; bzero(udpread_p, sizeof(*udpread_p)); ! udpread_p->src_ip = h->destip.s_addr; udpread_p->d_port = h->myport; udpread_p->buffer_size = len; udpread_p->buffer.segment = VTOPSEG(data_buffer); The Intel's document of pxe says DestIP: Only accept packets sent to this IP address. If this is zero, packets sent to any IP address are accepted http://www.intel.com/design/archives/wfm/downloads/pxespec.htm I remove line of udpread_p->dest_ip... , And added the line udpread_p->src_ip... for security. I wonder why NFS Server of FreeBSD is success at the code of current. Unfortunately a reason isn't understood. --- my test enviroment Boot server CentOS6.7 and CentOS7.1. Diskless client FreeBSD-9.3 Hardware1: virtual machin of VMware ESXi 6.0 Hardware2: M/B SuperMicro X8SIL-F (IntelPXE)