I download the vpnc client from the following link   https://www.unix-ag.uni-kl.de/~massar/vpnc/Then I installed the vpnc on my Linux red-hat machine ( version 6.x ) as the following:tar zxf vpnc-0.5.3.tar.gzcd vpnc-0.5.3make.makemake: libgcrypt-config: Command not foundgcc -O3 -g -W -Wall -Wmissing-declarations -Wwrite-strings  -DVERSION=\0.5.3\   -c -    o isakmp-pkt.o isakmp-pkt.cIn file included from isakmp-pkt.c:31:math_group.h:38:20: error: gcrypt.h: No such file or directoryIn file included from isakmp-pkt.c:31:math_group.h:62: error: expected specifier-qualifier-list before gcry_mpi_tIn file included from vpnc.h:24,             from isakmp-pkt.c:32:tunip.h:43: error: expected specifier-qualifier-list before gcry_cipher_hd_tisakmp-pkt.c: In function parse_isakmp_packet:isakmp-pkt.c:823: warning: format %d expects type int, but argument 2 has type     size_tmake: *** [isakmp-pkt.o] Error 1please advice why I get errors about  libgcrypt and libgcrypt ??  (those rpms already installed on my machine , so whats the problem here ? )I checked the rpm's: and they installed on my linux machinerpm -qa | grep libgcryptlibgcrypt-1.4.5-9.el6_2.2.x86_64libgcrypt-1.4.5-9.el6_2.2.i686rpm -qa | grep gcryptlibgcrypt-1.4.5-9.el6_2.2.x86_64libgcrypt-1.4.5-9.el6_2.2.i686remark - the link below described the vpnc installation:http://floppsie.comp.glam.ac.uk/Glamorgan/gaius/networks/13.html
linux + get errors about libraries inspite lib rpm's already installed
linux;libraries;vpn;cisco