Updated the dependency list

[mhaghighat]

libssl-dev is needed for configuring with openssl

[dlenski]

libssl-dev is needed for configuring with openssl

The core OpenConnect developers recommend building with GnuTLS, not with OpenSSL… is there a reason you need/want to build with GnuTLS instead?

[mhaghighat]

I didn't want to build is with GnuTLS or anything. I just followed the installation instruction here on a clean Ubuntu and it gave this error when running the ./configure:

Error: Could not build against OpenSSL

The solution in this link helped to resolve this error, which was installing the libssl-dev package.

[dlenski]

I just followed the installation instruction here on a clean Ubuntu and it gave this error when running the ./configure:

Error: Could not build against OpenSSL

What does the end of the ./configure output show? (Here's what I see on my Ubuntu 18.04 system, with the GnuTLS dev libraries installed, as is the intention of the build instructions.)

$ ./configure
...
BUILD OPTIONS:
  SSL library:            GnuTLS
  PKCS#11 support:        GnuTLS
  DTLS support:           yes
  ESP support:            yes
  libproxy support:       yes
  RSA SecurID support:    yes
  PSKC OATH file support: no
  GSSAPI support:         yes
  Yubikey support:        yes
  LZ4 compression:        yes
  Java bindings:          no
  Build docs:             yes
  Unit tests:             yes
  Net namespace tests:    no

(I should also point out that you should build from the upstream project, https://gitlab.com/openconnect/openconnect/, which supports GlobalProtect as of v8.0; this repo is only retained for historical reasons and a few open issues trackers for less-understood corners of the GlobalProtect protocol.)

[mhaghighat]

It looks like this now:

BUILD OPTIONS:
  SSL library:            GnuTLS
  PKCS#11 support:        GnuTLS
  DTLS support:           yes
  ESP support:            yes
  libproxy support:       yes
  RSA SecurID support:    no
  PSKC OATH file support: no
  GSSAPI support:         no
  Yubikey support:        no
  LZ4 compression:        no
  Java bindings:          no
  Build docs:             no
  Unit tests:             no

Please note that this is after installing that package. It used to give the abovementioned error before.

[dlenski]

Please note that this is after installing that package. It used to give the abovementioned error before.

Thanks, that's useful. Perhaps the configure script isn't detecting the build dependencies correctly. Let me make sure I have this 100% right so I can try to reproduce.

1. After installing libgnutls-dev, but before installing libssl-dev, you got Error: Could not build against OpenSSL when you ran ./configure
2. After installing both libgnutls-dev and libssl-dev, the ./configure script completed successfully and indicated that it would use GnuTLS

Is that right?

[mhaghighat]

That is right.
As another note, I installed libgnutls28-dev as you've mentioned in the comment there.