In this context MAC stands for Message Authentication Code. It's a cryptographic term, and it has nothing at all to do with Ethernet MAC (Media Access Control) addresses. A.7.2 Why do I see ‘Fatal: Protocol error: Expected control record’ in PSCP? This happens because PSCP was expecting to see data from the server that was part of the PSCP protocol exchange, and instead it saw data that it couldn't make any sense of at all.
This almost always happens because the startup scripts in your account on the server machine are generating output. This is impossible for PSCP, or any other SCP client, to work around. You should never use startup files (.bashrc, .cshrc and so on) which generate output in non-interactive sessions. This is not actually a PuTTY problem. If PSCP fails in this way, then all other SCP clients are likely to fail in exactly the same way. The problem is at the server end.
A.7.3 I clicked on a colour in the Colours panel, and the colour didn't change in my terminal. That isn't how you're supposed to use the Colours panel.
During the course of a session, PuTTY potentially uses all the colours listed in the Colours panel. It's not a question of using only one of them and you choosing which one; PuTTY will use them all. The purpose of the Colours panel is to let you adjust the appearance of all the colours. So to change the colour of the cursor, for example, you would select ‘Cursor Colour’, press the ‘Modify’ button, and select a new colour from the dialog box that appeared. Similarly, if you want your session to appear in green, you should select ‘Default Foreground’ and press ‘Modify’. Clicking on ‘ANSI Green’ won't turn your session green; it will only allow you to adjust the shade of green used when PuTTY is instructed by the server to display green text.
A.7.4 Plink on Windows 95 says it can't find WS2_32.DLL. Plink requires the extended Windows network library, WinSock version 2. This is installed as standard on Windows 98 and above, and on Windows NT, and even on later versions of Windows 95; but early Win95 installations don't have it.
In order to use Plink on these systems, you will need to download the WinSock 2 upgrade
: http://www.microsoft.com/windows95/downloads/contents/
wuadmintools/s_wunetworkingtools/w95sockets2/
A.7.5 After trying to establish an SSH-2 connection, PuTTY says ‘Out of memory’ and dies. If this happens just while the connection is starting up, this often indicates that for some reason the client and server have failed to establish a session encryption key. Somehow, they have performed calculations that should have given each of them the same key, but have ended up with different keys; so data encrypted by one and decrypted by the other looks like random garbage.
This causes an ‘out of memory’ error because the first encrypted data PuTTY expects to see is the length of an SSH message. Normally this will be something well under 100 bytes. If the decryption has failed, PuTTY will see a completely random length in the region of two gigabytes, and will try to allocate enough memory to store this non-existent message. This will immediately lead to it thinking it doesn't have enough memory, and panicking.
If this happens to you, it is quite likely to still be a PuTTY bug and you should report it (although it might be a bug in your SSH server instead); but it doesn't necessarily mean you've actually run out of memory.
A.7.6 When attempting a file transfer, either PSCP or PSFTP says ‘Out of memory’ and dies. This is almost always caused by your login scripts on the server generating output. PSCP or PSFTP will receive that output when they were expecting to see the start of a file transfer protocol, and they will attempt to interpret the output as file-transfer protocol. This will usually lead to an ‘out of memory’ error for much the same reasons as given in question A.7.5
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