Comment from Marco [here](https://github.com/bitcoin/bitcoin/pull/19954#discussion_r503075378):
> + make -C src --jobs=1 check-security V=1
make: Entering directory '/bitcoin/distsrc-x86_64-linux-gnu/src'
Checking binary security...
READELF=/gnu/store/pzq9s5ldl90h72p26jkdakyccdg9ib3k-profile/bin/x86_64-linux-gnu-readelf OBJDUMP=x86_64-linux-gnu-objdump OTOOL= /gnu/store/pzq9s5ldl90h72p26jkdakyccdg9ib3k-profile/bin/python3.7 ../contrib/devtools/security-check.py bitcoind  bitcoin-cli bitcoin-tx bitcoin-wallet test/test_bitcoin bench/bench_bitcoin qt/bitcoin-qt  
make: Leaving directory '/bitcoin/distsrc-x86_64-linux-gnu/src'
> + case "$HOST" in
> + make -C src --jobs=1 check-symbols V=1
make: Entering directory '/bitcoin/distsrc-x86_64-linux-gnu/src'
Checking glibc back compat...
READELF=/gnu/store/pzq9s5ldl90h72p26jkdakyccdg9ib3k-profile/bin/x86_64-linux-gnu-readelf CPPFILT=/gnu/store/pzq9s5ldl90h72p26jkdakyccdg9ib3k-profile/bin/x86_64-linux-gnu-c++filt /gnu/store/pzq9s5ldl90h72p26jkdakyccdg9ib3k-profile/bin/python3.7 ../contrib/devtools/symbol-check.py bitcoind  bitcoin-cli bitcoin-tx bitcoin-wallet test/test_bitcoin bench/bench_bitcoin qt/bitcoin-qt  
test/test_bitcoin: export of symbol in6addr_loopback not allowed
test/test_bitcoin: failed EXPORTED_SYMBOLS
make: *** [Makefile:20952: check-symbols] Error 1
make: Leaving directory '/bitcoin/distsrc-x86_64-linux-gnu/src'

**test/test_bitcoin: export of symbol in6addr_loopback not allowed**
BOOST_CHECK_EQUAL(subnet.ToString(), "1.2.3.4/32");
    subnet = CSubNet(ResolveIP("1.2.3.4"), 8);
    BOOST_CHECK_EQUAL(subnet.ToString(), "1.0.0.0/8");
    subnet = CSubNet(ResolveIP("1.2.3.4"), 0);
    BOOST_CHECK_EQUAL(subnet.ToString(), "0.0.0.0/0");
    subnet = CSubNet(ResolveIP("1.2.3.4"), ResolveIP("255.255.255.255"));
    BOOST_CHECK_EQUAL(subnet.ToString(), "1.2.3.4/32");
    subnet = CSubNet(ResolveIP("1.2.3.4"), ResolveIP("255.0.0.0"));
    BOOST_CHECK_EQUAL(subnet.ToString(), "1.0.0.0/8");
    subnet = CSubNet(ResolveIP("1.2.3.4"), ResolveIP("0.0.0.0"));
    BOOST_CHECK_EQUAL(subnet.ToString(), "0.0.0.0/0");
    BOOST_CHECK(CSubNet(ResolveIP("1:2:3:4:5:6:7:8")).IsValid());
    BOOST_CHECK(CSubNet(ResolveIP("1:2:3:4:5:6:7:8")).Match(ResolveIP("1:2:3:4:5:6:7:8")));
    BOOST_CHECK(!CSubNet(ResolveIP("1:2:3:4:5:6:7:8")).Match(ResolveIP("1:2:3:4:5:6:7:9")));
    BOOST_CHECK(CSubNet(ResolveIP("1:2:3:4:5:6:7:8")).ToString() == "1:2:3:4:5:6:7:8/128");
    
    BOOST_CHECK(!CSubNet(ResolveIP("1.1.1.1"), ResolveIP("ffff::")).IsValid());
    BOOST_CHECK(!CSubNet(ResolveIP("::1"), ResolveIP("255.0.0.0")).IsValid());
    
    BOOST_CHECK(!CSubNet(ResolveIP("5wyqrzbvrdsumnok.onion"), ResolveIP("255.0.0.0")).IsValid());
    subnet = ResolveSubNet("1.2.3.4/255.255.255.255");
    BOOST_CHECK_EQUAL(subnet.ToString(), "1.2.3.4/32");
    subnet = ResolveSubNet("1.2.3.4/255.255.255.254");
    BOOST_CHECK_EQUAL(subnet.ToString(), "1.2.3.4/31");
    subnet = ResolveSubNet("1.2.3.4/255.255.255.252");
    BOOST_CHECK_EQUAL(subnet.ToString(), "1.2.3.4/30");
    subnet = ResolveSubNet("1.2.3.4/255.255.255.248");
    BOOST_CHECK_EQUAL(subnet.ToString(), "1.2.3.0/29");
    subnet = ResolveSubNet("1.2.3.4/255.255.255.240");
    BOOST_CHECK_EQUAL(subnet.ToString(), "1.2.3.0/28");