Following way timeout can be change in Teradata Gateway:
The default value for connection timeout is 60 seconds and we are changing it to 120 seconds in that example.
#tdatcmd
# gtwcontrol -d
gtwcontrol: gtwversion 15.10.00.01
gdo version: 6, created on Tue Feb 12 10:37:38 2019
systemname: TD-EXPRESS
number of host groups: 1, number of gateway vprocs 1
max logfile size: 5000000
event trace cnt: 500
gtwglobal logon name: DBC
Send DBS error to client: no
TDGSS Library Version..........: 15.10.0.6
hgid: 1
assign vprocid: 22528
assigntrace: no
logons enabled: yes
session timeout in minutes: 20
connection timeout in seconds: 60
keepalive timeout in minutes: 10
max sessions per gateway: 600
iothread check frequency in minutes: 10
max io threads per type (msg/net): 50
initial io threads per type (msg/net): 25
allow gateway testing enabled: no
External Authentication: on
Append Domain Name: no
Reserved for Backdown: 0
Require Confidentiality: no
Send Connect Response with Integrity Only: no
Connection trace: no
Local PE Preferred Percent: 0%
TCP Socket SND/RCV Buffer Size: default (65587)
vproc id: 22528 status: Online
# gtwcontrol -c 120
gtwcontrol: gtwversion 15.10.00.01
gtwcontrol: gtw gdo successfully updated
# gtwcontrol -d
gtwcontrol: gtwversion 15.10.00.01
gdo version: 6, created on Tue Feb 12 10:37:38 2019
systemname: TD-EXPRESS
number of host groups: 1, number of gateway vprocs 1
max logfile size: 5000000
event trace cnt: 500
gtwglobal logon name: DBC
Send DBS error to client: no
TDGSS Library Version..........: 15.10.0.6
hgid: 1
assign vprocid: 22528
assigntrace: no
logons enabled: yes
session timeout in minutes: 20
connection timeout in seconds: 120
keepalive timeout in minutes: 10
max sessions per gateway: 600
iothread check frequency in minutes: 10
max io threads per type (msg/net): 50
initial io threads per type (msg/net): 25
allow gateway testing enabled: no
External Authentication: on
Append Domain Name: no
Reserved for Backdown: 0
Require Confidentiality: no
Send Connect Response with Integrity Only: no
Connection trace: no
Local PE Preferred Percent: 0%
TCP Socket SND/RCV Buffer Size: default (65587)
vproc id: 22528 status: Online