/etc/moduli
file contains the system-wide Diffie-Hellman prime moduli for
sshd(8).
Each line in this file contains the following fields: Time, Type, Tests, Tries, Size, Generator, Modulus. The fields are separated by white space (tab or blank).
Time
: yyyymmddhhmmss
.
Specifies the system time that the line was appended to the file.
The value 00000000000000 means unknown (historic).
Type
: decimal
.
Specifies the internal structure of the prime modulus.
Tests
: decimal
(bit
field)
.
Specifies the methods used in checking for primality.
Usually, more than one test is used.
Tries
: decimal
.
Depends on the value of the highest valid Test bit,
where the method specified is:
Size
: decimal
.
Specifies the number of the most significant bit (0 to M).
Generator
: hex
string
.
Specifies the best generator for a Diffie-Hellman exchange.
0 = unknown or variable,
2, 3, 5, etc.
Modulus
: hex
string
.
The prime modulus.
The file should be searched for moduli that meet the appropriate Time, Size and Generator criteria. When more than one meet the criteria, the selection should be weighted toward newer moduli, without completely disqualifying older moduli.
Note that sshd(8) uses only the Size criteria and then selects a modulus at random if more than one meet the Size criteria.
/etc/moduli